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/node/LongNode.java

package com.fasterxml.jackson.databind.node;

import java.io.IOException;
import java.math.BigDecimal;
import java.math.BigInteger;

import com.fasterxml.jackson.core.*;
import com.fasterxml.jackson.core.io.NumberOutput;
import com.fasterxml.jackson.databind.SerializerProvider;


/**
 * Numeric node that contains simple 64-bit integer values.
 */
@SuppressWarnings("serial")
public class LongNode
    extends NumericNode
{
    protected final long _value;

    /* 
    ************************************************
    * Construction
    ************************************************
    */

    public LongNode(long v) { _value = v; }

    public static LongNode valueOf(long l) { return new LongNode(l); }

    /* 
    ************************************************
    * Overrridden JsonNode methods
    ************************************************
    */

    @Override public JsonToken asToken() { return JsonToken.VALUE_NUMBER_INT; }

    @Override
    public JsonParser.NumberType numberType() { return JsonParser.NumberType.LONG; }


    @Override
    public boolean isIntegralNumber() { return true; }

    @Override
    public boolean isLong() { return true; }

    @Override public boolean canConvertToInt() {
        return (_value >= Integer.MIN_VALUE && _value <= Integer.MAX_VALUE);
    }
    @Override public boolean canConvertToLong() { return true; }
    
    @Override
    public Number numberValue() {
        return Long.valueOf(_value);
    }

    @Override
    public short shortValue() { return (short) _value; }

    @Override
    public int intValue() { return (int) _value; }

    @Override
    public long longValue() { return _value; }

    @Override
    public float floatValue() { return _value; }

    @Override
    public double doubleValue() { return _value; }

    @Override
    public BigDecimal decimalValue() { return BigDecimal.valueOf(_value); }

    @Override
    public BigInteger bigIntegerValue() { return BigInteger.valueOf(_value); }

    @Override
    public String asText() {
        return NumberOutput.toString(_value);
    }

    @Override
    public boolean asBoolean(boolean defaultValue) {
        return _value != 0;
    }
    
    @Override
    public final void serialize(JsonGenerator g, SerializerProvider provider)
        throws IOException
    {
        g.writeNumber(_value);
    }

    @Override
    public boolean equals(Object o)
    {
        if (o == this) return true;
        if (o == null) return false;
        if (o instanceof LongNode) {
            return ((LongNode) o)._value == _value;
        }
        return false;
    }

    @Override
    public int hashCode() {
        return ((int) _value) ^ (int) (_value >> 32);
    }
}

⏎ com/fasterxml/jackson/databind/node/LongNode.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 

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⇑⇑ Jackson - Java JSON library