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

Jackson Annotations Source Code files are provided in the source packge (jackson-annotations-2.12.4-sources.jar). You can download it at Jackson Maven Website.

You can also browse Jackson Annotations Source Code below:

⏎ com/fasterxml/jackson/databind/ser/std/ToStringSerializer.java

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

import com.fasterxml.jackson.databind.annotation.JacksonStdImpl;

/**
 * Simple general purpose serializer, useful for any
 * type for which {@link Object#toString} returns the desired JSON
 * value.
 *<p>
 * Since 2.10 extends {@link ToStringSerializerBase}
 */
@JacksonStdImpl
@SuppressWarnings("serial")
public class ToStringSerializer
    extends ToStringSerializerBase
{
    /**
     * Singleton instance to use.
     */
    public final static ToStringSerializer instance = new ToStringSerializer();

    /**
     *<p>
     * Note: usually you should NOT create new instances, but instead use
     * {@link #instance} which is stateless and fully thread-safe. However,
     * there are cases where constructor is needed; for example,
     * when using explicit serializer annotations like
     * {@link com.fasterxml.jackson.databind.annotation.JsonSerialize#using}.
     */
    public ToStringSerializer() { super(Object.class); }

    /**
     * Sometimes it may actually make sense to retain actual handled type.
     * 
     * @since 2.5
     */
    public ToStringSerializer(Class<?> handledType) {
        super(handledType);
    }

    @Override
    public final String valueToString(Object value) {
        return value.toString();
    }
}

⏎ com/fasterxml/jackson/databind/ser/std/ToStringSerializer.java

 

⇒ Jackson Dataformat Extensions

⇐ Jackson Data Binding Source Code

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⇑⇑ Jackson - Java JSON library