Jackson is "the Java JSON library" or "the best JSON parser for Java". Or simply as "JSON for Java".

Jackson Databind Source Code files are provided in the source packge (jackson-databind-2.14.0-sources.jar). You can download it at Jackson Maven Website.

You can also browse Jackson Databind Source Code below:

⏎ com/fasterxml/jackson/databind/deser/std/PrimitiveArrayDeserializers.java

package com.fasterxml.jackson.databind.deser.std;

import java.io.IOException;
import java.lang.reflect.Array;
import java.util.Arrays;
import java.util.Objects;

import com.fasterxml.jackson.annotation.JsonFormat;
import com.fasterxml.jackson.annotation.Nulls;

import com.fasterxml.jackson.core.*;
import com.fasterxml.jackson.core.exc.StreamReadException;
import com.fasterxml.jackson.databind.*;
import com.fasterxml.jackson.databind.annotation.JacksonStdImpl;
import com.fasterxml.jackson.databind.deser.ContextualDeserializer;
import com.fasterxml.jackson.databind.deser.NullValueProvider;
import com.fasterxml.jackson.databind.deser.impl.NullsConstantProvider;
import com.fasterxml.jackson.databind.deser.impl.NullsFailProvider;
import com.fasterxml.jackson.databind.exc.InvalidNullException;
import com.fasterxml.jackson.databind.jsontype.TypeDeserializer;
import com.fasterxml.jackson.databind.type.LogicalType;
import com.fasterxml.jackson.databind.util.AccessPattern;
import com.fasterxml.jackson.databind.util.ArrayBuilders;

/**
 * Container for deserializers used for instantiating "primitive arrays",
 * arrays that contain non-object java primitive types.
 */
@SuppressWarnings("serial")
public abstract class PrimitiveArrayDeserializers<T> extends StdDeserializer<T>
    implements ContextualDeserializer // since 2.7
{
    /**
     * Specific override for this instance (from proper, or global per-type overrides)
     * to indicate whether single value may be taken to mean an unwrapped one-element array
     * or not. If null, left to global defaults.
     *
     * @since 2.7
     */
    protected final Boolean _unwrapSingle;

    // since 2.9
    private transient Object _emptyValue;

    /**
     * Flag that indicates need for special handling; either failing
     * (throw exception) or skipping
     */
    protected final NullValueProvider _nuller;

    /*
    /********************************************************
    /* Life-cycle
    /********************************************************
     */
    
    protected PrimitiveArrayDeserializers(Class<T> cls) {
        super(cls);
        _unwrapSingle = null;
        _nuller = null;
    }

    /**
     * @since 2.7
     */
    protected PrimitiveArrayDeserializers(PrimitiveArrayDeserializers<?> base,
            NullValueProvider nuller, Boolean unwrapSingle) {
        super(base._valueClass);
        _unwrapSingle = unwrapSingle;
        _nuller = nuller;
    }
    
    public static JsonDeserializer<?> forType(Class<?> rawType)
    {
        // Start with more common types...
        if (rawType == Integer.TYPE) {
            return IntDeser.instance;
        }
        if (rawType == Long.TYPE) {
            return LongDeser.instance;
        }
        
        if (rawType == Byte.TYPE) {
            return new ByteDeser();
        }
        if (rawType == Short.TYPE) {
            return new ShortDeser();
        }
        if (rawType == Float.TYPE) {
            return new FloatDeser();
        }
        if (rawType == Double.TYPE) {
            return new DoubleDeser();
        }
        if (rawType == Boolean.TYPE) {
            return new BooleanDeser();
        }
        if (rawType == Character.TYPE) {
            return new CharDeser();
        }
        throw new IllegalStateException();
    }

    @Override
    public JsonDeserializer<?> createContextual(DeserializationContext ctxt,
            BeanProperty property) throws JsonMappingException
    {
        Boolean unwrapSingle = findFormatFeature(ctxt, property, _valueClass,
                JsonFormat.Feature.ACCEPT_SINGLE_VALUE_AS_ARRAY);
        NullValueProvider nuller = null;

        Nulls nullStyle = findContentNullStyle(ctxt, property);
        if (nullStyle == Nulls.SKIP) {
            nuller = NullsConstantProvider.skipper();
        } else if (nullStyle == Nulls.FAIL) {
            if (property == null) {
                // 09-Dec-2019, tatu: [databind#2567] need to ensure correct target type
                nuller = NullsFailProvider.constructForRootValue(ctxt.constructType(_valueClass.getComponentType()));
            } else {
                // 09-Dec-2019, tatu: [databind#2567] need to ensure correct target type
                nuller = NullsFailProvider.constructForProperty(property, property.getType().getContentType());
            }
        }
        if ((Objects.equals(unwrapSingle, _unwrapSingle)) && (nuller == _nuller)) {
            return this;
        }
        return withResolved(nuller, unwrapSingle);
    }

    /*
    /********************************************************
    /* Abstract methods for sub-classes to implement
    /********************************************************
     */

    /**
     * @since 2.9
     */
    protected abstract T _concat(T oldValue, T newValue);

    protected abstract T handleSingleElementUnwrapped(JsonParser p,
            DeserializationContext ctxt) throws IOException;

    /**
     * @since 2.9
     */
    protected abstract PrimitiveArrayDeserializers<?> withResolved(NullValueProvider nuller,
            Boolean unwrapSingle);

    // since 2.9
    protected abstract T _constructEmpty();
    
    /*
    /********************************************************
    /* Default implementations
    /********************************************************
     */

    @Override // since 2.12
    public LogicalType logicalType() {
        return LogicalType.Array;
    }
    
    @Override // since 2.9
    public Boolean supportsUpdate(DeserializationConfig config) {
        return Boolean.TRUE;
    }

    @Override
    public AccessPattern getEmptyAccessPattern() {
        // Empty values shareable freely
        return AccessPattern.CONSTANT;
    }
    
    @Override // since 2.9
    public Object getEmptyValue(DeserializationContext ctxt) throws JsonMappingException {
        Object empty = _emptyValue;
        if (empty == null) {
            _emptyValue = empty = _constructEmpty();
        }
        return empty;
    }

    @Override
    public Object deserializeWithType(JsonParser p, DeserializationContext ctxt,
            TypeDeserializer typeDeserializer) throws IOException
    {
        // Should there be separate handling for base64 stuff?
        // for now this should be enough:
        return typeDeserializer.deserializeTypedFromArray(p, ctxt);
    }

    @Override
    public T deserialize(JsonParser p, DeserializationContext ctxt, T existing) throws IOException
    {
        T newValue = deserialize(p, ctxt);
        if (existing == null) {
            return newValue;
        }
        int len = Array.getLength(existing);
        if (len == 0) {
            return newValue;
        }
        return _concat(existing, newValue);
    }

    /*
    /********************************************************
    /* Helper methods for sub-classes
    /********************************************************
     */

    @SuppressWarnings("unchecked")
    protected T handleNonArray(JsonParser p, DeserializationContext ctxt) throws IOException
    {
        // Empty String can become null...
        if (p.hasToken(JsonToken.VALUE_STRING)) {
            return _deserializeFromString(p, ctxt);
        }
        boolean canWrap = (_unwrapSingle == Boolean.TRUE) ||
                ((_unwrapSingle == null) &&
                        ctxt.isEnabled(DeserializationFeature.ACCEPT_SINGLE_VALUE_AS_ARRAY));
        if (canWrap) {
            return handleSingleElementUnwrapped(p, ctxt);
        }
        return (T) ctxt.handleUnexpectedToken(_valueClass, p);
    }

    protected void _failOnNull(DeserializationContext ctxt) throws IOException
    {
        throw InvalidNullException.from(ctxt, null, ctxt.constructType(_valueClass));
    }

    /*
    /********************************************************
    /* Actual deserializers: efficient String[], char[] deserializers
    /********************************************************
     */

    @JacksonStdImpl
    final static class CharDeser
        extends PrimitiveArrayDeserializers<char[]>
    {
        private static final long serialVersionUID = 1L;

        public CharDeser() { super(char[].class); }
        protected CharDeser(CharDeser base, NullValueProvider nuller, Boolean unwrapSingle) {
            super(base, nuller, unwrapSingle);
        }

        @Override
        protected PrimitiveArrayDeserializers<?> withResolved(NullValueProvider nuller,
                Boolean unwrapSingle) {
            // 11-Dec-2015, tatu: Not sure how re-wrapping would work; omit
            return this;
        }

        @Override
        protected char[] _constructEmpty() {
            return new char[0];
        }

        @Override
        public char[] deserialize(JsonParser p, DeserializationContext ctxt) throws IOException
        {
            /* Won't take arrays, must get a String (could also
             * convert other tokens to Strings... but let's not bother
             * yet, doesn't seem to make sense)
             */
            if (p.hasToken(JsonToken.VALUE_STRING)) {
                // note: can NOT return shared internal buffer, must copy:
                char[] buffer = p.getTextCharacters();
                int offset = p.getTextOffset();
                int len = p.getTextLength();
    
                char[] result = new char[len];
                System.arraycopy(buffer, offset, result, 0, len);
                return result;
            }
            if (p.isExpectedStartArrayToken()) {
                // Let's actually build as a String, then get chars
                StringBuilder sb = new StringBuilder(64);
                JsonToken t;
                while ((t = p.nextToken()) != JsonToken.END_ARRAY) {
                    String str;
                    if (t == JsonToken.VALUE_STRING) {
                        str = p.getText();
                    } else if (t == JsonToken.VALUE_NULL) {
                        if (_nuller != null) {
                            _nuller.getNullValue(ctxt);
                            continue;
                        }
                        _verifyNullForPrimitive(ctxt);
                        str = "\0";
                    } else {
                        CharSequence cs = (CharSequence) ctxt.handleUnexpectedToken(Character.TYPE, p);
                        str = cs.toString();
                    }
                    if (str.length() != 1) {
                        ctxt.reportInputMismatch(this,
"Cannot convert a JSON String of length %d into a char element of char array", str.length());
                    }
                    sb.append(str.charAt(0));
                }
                return sb.toString().toCharArray();
            }
            // or, maybe an embedded object?
            if (p.hasToken(JsonToken.VALUE_EMBEDDED_OBJECT)) {
                Object ob = p.getEmbeddedObject();
                if (ob == null) return null;
                if (ob instanceof char[]) {
                    return (char[]) ob;
                }
                if (ob instanceof String) {
                    return ((String) ob).toCharArray();
                }
                // 04-Feb-2011, tatu: byte[] can be converted; assuming base64 is wanted
                if (ob instanceof byte[]) {
                    return Base64Variants.getDefaultVariant().encode((byte[]) ob, false).toCharArray();
                }
                // not recognized, just fall through
            }
            return (char[]) ctxt.handleUnexpectedToken(_valueClass, p);
        }

        @Override
        protected char[] handleSingleElementUnwrapped(JsonParser p,
                DeserializationContext ctxt) throws IOException {
            // not sure how this should work...
            return (char[]) ctxt.handleUnexpectedToken(_valueClass, p);
        }

        @Override
        protected char[] _concat(char[] oldValue, char[] newValue) {
            int len1 = oldValue.length;
            int len2 = newValue.length;
            char[] result = Arrays.copyOf(oldValue, len1+len2);
            System.arraycopy(newValue, 0, result, len1, len2);
            return result;
        }
    }

    /*
    /**********************************************************
    /* Actual deserializers: primivate array desers
    /**********************************************************
     */

    @JacksonStdImpl
    final static class BooleanDeser
        extends PrimitiveArrayDeserializers<boolean[]>
    {
        private static final long serialVersionUID = 1L;

        public BooleanDeser() { super(boolean[].class); }
        protected BooleanDeser(BooleanDeser base, NullValueProvider nuller, Boolean unwrapSingle) {
            super(base, nuller, unwrapSingle);
        }

        @Override
        protected PrimitiveArrayDeserializers<?> withResolved(NullValueProvider nuller,
                Boolean unwrapSingle) {
            return new BooleanDeser(this, nuller, unwrapSingle);
        }

        @Override
        protected boolean[] _constructEmpty() {
            return new boolean[0];
        }

        @Override
        public boolean[] deserialize(JsonParser p, DeserializationContext ctxt)
            throws IOException
        {
            if (!p.isExpectedStartArrayToken()) {
                return handleNonArray(p, ctxt);
            }
            ArrayBuilders.BooleanBuilder builder = ctxt.getArrayBuilders().getBooleanBuilder();
            boolean[] chunk = builder.resetAndStart();
            int ix = 0;

            try {
                JsonToken t;
                while ((t = p.nextToken()) != JsonToken.END_ARRAY) {
                    boolean value;
                    if (t == JsonToken.VALUE_TRUE) {
                        value = true;
                    } else if (t == JsonToken.VALUE_FALSE) {
                        value = false;
                    } else if (t == JsonToken.VALUE_NULL) {
                        if (_nuller != null) {
                            _nuller.getNullValue(ctxt);
                            continue;
                        }
                        _verifyNullForPrimitive(ctxt);
                        value = false;
                    } else {
                        value = _parseBooleanPrimitive(p, ctxt);
                    }
                    if (ix >= chunk.length) {
                        chunk = builder.appendCompletedChunk(chunk, ix);
                        ix = 0;
                    }
                    chunk[ix++] = value;
                }
            } catch (Exception e) {
                throw JsonMappingException.wrapWithPath(e, chunk, builder.bufferedSize() + ix);
            }
            return builder.completeAndClearBuffer(chunk, ix);
        }

        @Override
        protected boolean[] handleSingleElementUnwrapped(JsonParser p,
                DeserializationContext ctxt) throws IOException {
            return new boolean[] { _parseBooleanPrimitive(p, ctxt) };
        }

        @Override
        protected boolean[] _concat(boolean[] oldValue, boolean[] newValue) {
            int len1 = oldValue.length;
            int len2 = newValue.length;
            boolean[] result = Arrays.copyOf(oldValue, len1+len2);
            System.arraycopy(newValue, 0, result, len1, len2);
            return result;
        }
    }

    /**
     * When dealing with byte arrays we have one more alternative (compared
     * to int/long/shorts): base64 encoded data.
     */
    @JacksonStdImpl
    final static class ByteDeser
        extends PrimitiveArrayDeserializers<byte[]>
    {
        private static final long serialVersionUID = 1L;

        public ByteDeser() { super(byte[].class); }
        protected ByteDeser(ByteDeser base, NullValueProvider nuller,Boolean unwrapSingle) {
            super(base, nuller, unwrapSingle);
        }

        @Override
        protected PrimitiveArrayDeserializers<?> withResolved(NullValueProvider nuller,
                Boolean unwrapSingle) {
            return new ByteDeser(this, nuller, unwrapSingle);
        }

        @Override
        protected byte[] _constructEmpty() {
            return new byte[0];
        }

        @Override // since 2.12
        public LogicalType logicalType() {
            // 30-May-2020, tatu: while technically an array, logically contains
            //    binary data so...
            return LogicalType.Binary;
        }
        
        @Override
        public byte[] deserialize(JsonParser p, DeserializationContext ctxt) throws IOException
        {
            JsonToken t = p.currentToken();
            
            // Most likely case: base64 encoded String?
            if (t == JsonToken.VALUE_STRING) {
                try {
                    return p.getBinaryValue(ctxt.getBase64Variant());
                } catch (StreamReadException e) {
                    // 25-Nov-2016, tatu: related to [databind#1425], try to convert
                    //   to a more usable one, as it's not really a JSON-level parse
                    //   exception, but rather binding from JSON String into base64 decoded
                    //   binary data
                    String msg = e.getOriginalMessage();
                    if (msg.contains("base64")) {
                        return (byte[]) ctxt.handleWeirdStringValue(byte[].class,
                                p.getText(), msg);
                    }
                }
            }
            // 31-Dec-2009, tatu: Also may be hidden as embedded Object
            if (t == JsonToken.VALUE_EMBEDDED_OBJECT) {
                Object ob = p.getEmbeddedObject();
                if (ob == null) return null;
                if (ob instanceof byte[]) {
                    return (byte[]) ob;
                }
            }
            if (!p.isExpectedStartArrayToken()) {
                return handleNonArray(p, ctxt);
            }
            ArrayBuilders.ByteBuilder builder = ctxt.getArrayBuilders().getByteBuilder();
            byte[] chunk = builder.resetAndStart();
            int ix = 0;

            try {
                while ((t = p.nextToken()) != JsonToken.END_ARRAY) {
                    // whether we should allow truncating conversions?
                    byte value;
                    if (t == JsonToken.VALUE_NUMBER_INT) {
                        value = p.getByteValue(); // note: may throw due to overflow
                    } else {
                        // should probably accept nulls as 0
                        if (t == JsonToken.VALUE_NULL) {
                            if (_nuller != null) {
                                _nuller.getNullValue(ctxt);
                                continue;
                            }
                            _verifyNullForPrimitive(ctxt);
                            value = (byte) 0;
                        } else {
                            value = _parseBytePrimitive(p, ctxt);
                        }
                    }
                    if (ix >= chunk.length) {
                        chunk = builder.appendCompletedChunk(chunk, ix);
                        ix = 0;
                    }
                    chunk[ix++] = value;
                }
            } catch (Exception e) {
                throw JsonMappingException.wrapWithPath(e, chunk, builder.bufferedSize() + ix);
            }
            return builder.completeAndClearBuffer(chunk, ix);
        }

        @Override
        protected byte[] handleSingleElementUnwrapped(JsonParser p,
                DeserializationContext ctxt) throws IOException
        {
            byte value;
            JsonToken t = p.currentToken();
            if (t == JsonToken.VALUE_NUMBER_INT) {
                value = p.getByteValue(); // note: may throw due to overflow
            } else {
                // should probably accept nulls as 'false'
                if (t == JsonToken.VALUE_NULL) {
                    if (_nuller != null) {
                        _nuller.getNullValue(ctxt);
                        return (byte[]) getEmptyValue(ctxt);
                    }
                    _verifyNullForPrimitive(ctxt);
                    return null;
                }
                Number n = (Number) ctxt.handleUnexpectedToken(_valueClass.getComponentType(), p);
                value = n.byteValue();
            }
            return new byte[] { value };
        }

        @Override
        protected byte[] _concat(byte[] oldValue, byte[] newValue) {
            int len1 = oldValue.length;
            int len2 = newValue.length;
            byte[] result = Arrays.copyOf(oldValue, len1+len2);
            System.arraycopy(newValue, 0, result, len1, len2);
            return result;
        }
    }

    @JacksonStdImpl
    final static class ShortDeser
        extends PrimitiveArrayDeserializers<short[]>
    {
        private static final long serialVersionUID = 1L;

        public ShortDeser() { super(short[].class); }
        protected ShortDeser(ShortDeser base, NullValueProvider nuller, Boolean unwrapSingle) {
            super(base, nuller, unwrapSingle);
        }

        @Override
        protected PrimitiveArrayDeserializers<?> withResolved(NullValueProvider nuller,
                Boolean unwrapSingle) {
            return new ShortDeser(this, nuller, unwrapSingle);
        }

        @Override
        protected short[] _constructEmpty() {
            return new short[0];
        }

        @Override
        public short[] deserialize(JsonParser p, DeserializationContext ctxt) throws IOException
        {
            if (!p.isExpectedStartArrayToken()) {
                return handleNonArray(p, ctxt);
            }
            ArrayBuilders.ShortBuilder builder = ctxt.getArrayBuilders().getShortBuilder();
            short[] chunk = builder.resetAndStart();
            int ix = 0;

            try {
                JsonToken t;
                while ((t = p.nextToken()) != JsonToken.END_ARRAY) {
                    short value;
                    if (t == JsonToken.VALUE_NULL) {
                        if (_nuller != null) {
                            _nuller.getNullValue(ctxt);
                            continue;
                        }
                        _verifyNullForPrimitive(ctxt);
                        value = (short) 0;
                    } else {
                        value = _parseShortPrimitive(p, ctxt);
                    }
                    if (ix >= chunk.length) {
                        chunk = builder.appendCompletedChunk(chunk, ix);
                        ix = 0;
                    }
                    chunk[ix++] = value;
                }
            } catch (Exception e) {
                throw JsonMappingException.wrapWithPath(e, chunk, builder.bufferedSize() + ix);
            }
            return builder.completeAndClearBuffer(chunk, ix);
        }

        @Override
        protected short[] handleSingleElementUnwrapped(JsonParser p,
                DeserializationContext ctxt) throws IOException {
            return new short[] { _parseShortPrimitive(p, ctxt) };
        }

        @Override
        protected short[] _concat(short[] oldValue, short[] newValue) {
            int len1 = oldValue.length;
            int len2 = newValue.length;
            short[] result = Arrays.copyOf(oldValue, len1+len2);
            System.arraycopy(newValue, 0, result, len1, len2);
            return result;
        }
    }

    @JacksonStdImpl
    final static class IntDeser
        extends PrimitiveArrayDeserializers<int[]>
    {
        private static final long serialVersionUID = 1L;

        public final static IntDeser instance = new IntDeser();
        
        public IntDeser() { super(int[].class); }
        protected IntDeser(IntDeser base, NullValueProvider nuller, Boolean unwrapSingle) {
            super(base, nuller, unwrapSingle);
        }

        @Override
        protected PrimitiveArrayDeserializers<?> withResolved(NullValueProvider nuller,
                Boolean unwrapSingle) {
            return new IntDeser(this, nuller, unwrapSingle);
        }

        @Override
        protected int[] _constructEmpty() {
            return new int[0];
        }

        @Override
        public int[] deserialize(JsonParser p, DeserializationContext ctxt) throws IOException
        {
            if (!p.isExpectedStartArrayToken()) {
                return handleNonArray(p, ctxt);
            }
            ArrayBuilders.IntBuilder builder = ctxt.getArrayBuilders().getIntBuilder();
            int[] chunk = builder.resetAndStart();
            int ix = 0;

            try {
                JsonToken t;
                while ((t = p.nextToken()) != JsonToken.END_ARRAY) {
                    int value;
                    if (t == JsonToken.VALUE_NUMBER_INT) {
                        value = p.getIntValue();
                    } else if (t == JsonToken.VALUE_NULL) {
                        if (_nuller != null) {
                            _nuller.getNullValue(ctxt);
                            continue;
                        }
                        _verifyNullForPrimitive(ctxt);
                        value = 0;
                    } else {
                        value = _parseIntPrimitive(p, ctxt);
                    }
                    if (ix >= chunk.length) {
                        chunk = builder.appendCompletedChunk(chunk, ix);
                        ix = 0;
                    }
                    chunk[ix++] = value;
                }
            } catch (Exception e) {
                throw JsonMappingException.wrapWithPath(e, chunk, builder.bufferedSize() + ix);
            }
            return builder.completeAndClearBuffer(chunk, ix);
        }

        @Override
        protected int[] handleSingleElementUnwrapped(JsonParser p,
                DeserializationContext ctxt) throws IOException {
            return new int[] { _parseIntPrimitive(p, ctxt) };
        }

        @Override
        protected int[] _concat(int[] oldValue, int[] newValue) {
            int len1 = oldValue.length;
            int len2 = newValue.length;
            int[] result = Arrays.copyOf(oldValue, len1+len2);
            System.arraycopy(newValue, 0, result, len1, len2);
            return result;
        }
    }

    @JacksonStdImpl
    final static class LongDeser
        extends PrimitiveArrayDeserializers<long[]>
    {
        private static final long serialVersionUID = 1L;

        public final static LongDeser instance = new LongDeser();

        public LongDeser() { super(long[].class); }
        protected LongDeser(LongDeser base, NullValueProvider nuller, Boolean unwrapSingle) {
            super(base, nuller, unwrapSingle);
        }

        @Override
        protected PrimitiveArrayDeserializers<?> withResolved(NullValueProvider nuller,
                Boolean unwrapSingle) {
            return new LongDeser(this, nuller, unwrapSingle);
        }

        @Override
        protected long[] _constructEmpty() {
            return new long[0];
        }

        @Override
        public long[] deserialize(JsonParser p, DeserializationContext ctxt) throws IOException
        {
            if (!p.isExpectedStartArrayToken()) {
                return handleNonArray(p, ctxt);
            }
            ArrayBuilders.LongBuilder builder = ctxt.getArrayBuilders().getLongBuilder();
            long[] chunk = builder.resetAndStart();
            int ix = 0;

            try {
                JsonToken t;
                while ((t = p.nextToken()) != JsonToken.END_ARRAY) {
                    long value;
                    if (t == JsonToken.VALUE_NUMBER_INT) {
                        value = p.getLongValue();
                    } else if (t == JsonToken.VALUE_NULL) {
                        if (_nuller != null) {
                            _nuller.getNullValue(ctxt);
                            continue;
                        }
                        _verifyNullForPrimitive(ctxt);
                        value = 0L;
                    } else {
                        value = _parseLongPrimitive(p, ctxt);
                    }
                    if (ix >= chunk.length) {
                        chunk = builder.appendCompletedChunk(chunk, ix);
                        ix = 0;
                    }
                    chunk[ix++] = value;
                }
            } catch (Exception e) {
                throw JsonMappingException.wrapWithPath(e, chunk, builder.bufferedSize() + ix);
            }
            return builder.completeAndClearBuffer(chunk, ix);
        }

        @Override
        protected long[] handleSingleElementUnwrapped(JsonParser p,
                DeserializationContext ctxt) throws IOException {
            return new long[] { _parseLongPrimitive(p, ctxt) };
        }

        @Override
        protected long[] _concat(long[] oldValue, long[] newValue) {
            int len1 = oldValue.length;
            int len2 = newValue.length;
            long[] result = Arrays.copyOf(oldValue, len1+len2);
            System.arraycopy(newValue, 0, result, len1, len2);
            return result;
        }
    }

    @JacksonStdImpl
    final static class FloatDeser
        extends PrimitiveArrayDeserializers<float[]>
    {
        private static final long serialVersionUID = 1L;

        public FloatDeser() { super(float[].class); }
        protected FloatDeser(FloatDeser base, NullValueProvider nuller, Boolean unwrapSingle) {
            super(base, nuller, unwrapSingle);
        }

        @Override
        protected PrimitiveArrayDeserializers<?> withResolved(NullValueProvider nuller,
                Boolean unwrapSingle) {
            return new FloatDeser(this, nuller, unwrapSingle);
        }

        @Override
        protected float[] _constructEmpty() {
            return new float[0];
        }

        @Override
        public float[] deserialize(JsonParser p, DeserializationContext ctxt) throws IOException
        {
            if (!p.isExpectedStartArrayToken()) {
                return handleNonArray(p, ctxt);
            }
            ArrayBuilders.FloatBuilder builder = ctxt.getArrayBuilders().getFloatBuilder();
            float[] chunk = builder.resetAndStart();
            int ix = 0;

            try {
                JsonToken t;
                while ((t = p.nextToken()) != JsonToken.END_ARRAY) {
                    // whether we should allow truncating conversions?
                    if (t == JsonToken.VALUE_NULL) {
                        if (_nuller != null) {
                            _nuller.getNullValue(ctxt);
                            continue;
                        }
                    }
                    float value = _parseFloatPrimitive(p, ctxt);
                    if (ix >= chunk.length) {
                        chunk = builder.appendCompletedChunk(chunk, ix);
                        ix = 0;
                    }
                    chunk[ix++] = value;
                }
            } catch (Exception e) {
                throw JsonMappingException.wrapWithPath(e, chunk, builder.bufferedSize() + ix);
            }
            return builder.completeAndClearBuffer(chunk, ix);
        }

        @Override
        protected float[] handleSingleElementUnwrapped(JsonParser p,
                DeserializationContext ctxt) throws IOException {
            return new float[] { _parseFloatPrimitive(p, ctxt) };
        }

        @Override
        protected float[] _concat(float[] oldValue, float[] newValue) {
            int len1 = oldValue.length;
            int len2 = newValue.length;
            float[] result = Arrays.copyOf(oldValue, len1+len2);
            System.arraycopy(newValue, 0, result, len1, len2);
            return result;
        }
    }

    @JacksonStdImpl
    final static class DoubleDeser
        extends PrimitiveArrayDeserializers<double[]>
    {
        private static final long serialVersionUID = 1L;
        
        public DoubleDeser() { super(double[].class); }
        protected DoubleDeser(DoubleDeser base, NullValueProvider nuller, Boolean unwrapSingle) {
            super(base, nuller, unwrapSingle);
        }

        @Override
        protected PrimitiveArrayDeserializers<?> withResolved(NullValueProvider nuller,
                Boolean unwrapSingle) {
            return new DoubleDeser(this, nuller, unwrapSingle);
        }

        @Override
        protected double[] _constructEmpty() {
            return new double[0];
        }

        @Override
        public double[] deserialize(JsonParser p, DeserializationContext ctxt) throws IOException
        {
            if (!p.isExpectedStartArrayToken()) {
                return handleNonArray(p, ctxt);
            }
            ArrayBuilders.DoubleBuilder builder = ctxt.getArrayBuilders().getDoubleBuilder();
            double[] chunk = builder.resetAndStart();
            int ix = 0;

            try {
                JsonToken t;
                while ((t = p.nextToken()) != JsonToken.END_ARRAY) {
                    if (t == JsonToken.VALUE_NULL) {
                        if (_nuller != null) {
                            _nuller.getNullValue(ctxt);
                            continue;
                        }
                    }
                    double value = _parseDoublePrimitive(p, ctxt);
                    if (ix >= chunk.length) {
                        chunk = builder.appendCompletedChunk(chunk, ix);
                        ix = 0;
                    }
                    chunk[ix++] = value;
                }
            } catch (Exception e) {
                throw JsonMappingException.wrapWithPath(e, chunk, builder.bufferedSize() + ix);
            }
            return builder.completeAndClearBuffer(chunk, ix);
        }

        @Override
        protected double[] handleSingleElementUnwrapped(JsonParser p,
                DeserializationContext ctxt) throws IOException {
            return new double[] { _parseDoublePrimitive(p, ctxt) };
        }

        @Override
        protected double[] _concat(double[] oldValue, double[] newValue) {
            int len1 = oldValue.length;
            int len2 = newValue.length;
            double[] result = Arrays.copyOf(oldValue, len1+len2);
            System.arraycopy(newValue, 0, result, len1, len2);
            return result;
        }
    }
}

⏎ com/fasterxml/jackson/databind/deser/std/PrimitiveArrayDeserializers.java

Or download all of them as a single archive file:

File name: jackson-databind-2.14.0-sources.jar
File size: 1187952 bytes
Release date: 2022-11-05
Download 

⇒ Jackson Annotations Source Code

⇐ Download and Install Jackson Binary Package

⇑ Downloading and Reviewing jackson-*.jar

⇑⇑ Jackson - Java JSON library