SimplySerialize

<repository>
            <id>jitpack.io</id>
            <url>https://jitpack.io</url>
</repository>

<dependency>
        <groupId>com.github.ODINN555</groupId>
        <artifactId>SerializationsPlus</artifactId>
        <version>v1.0.3</version>
</dependency>

package me.example.plugin ;

import com.github.SimplySerialize.Serializations ;
import com.github.SimplySerialize.Serializer ;
import org.bukkit.plugin.java.JavaPlugin ;

import java.util.HashMap ;
import java.util.Map ;

public class ExamplePlugin extends JavaPlugin {

    @Override
    public void onEnable ( ) {
        // Register serializers on the enable of the plugin
        Serializations. registerSerializer ( new Serializer <ExampleObject > ( "ExampleObject",ExampleObject. class ) {
            @Override
            public Map < String, Object > serializeValue (ExampleObject exampleObject ) {
                // Always instance a new map here! do not use any short version of creating a map!
                Map < String,Object > map = new HashMap <> ( ) ;

                // Put the values of the object.
                // With this values you need to be able to create a new object.
                map. put ( "exampleKey", "exampleValue" ) ;
                return map ;
            }

            @Override
            public ExampleObject deserializeValue (Map < String, Object > map ) {
                // Retrieve the values and create a new object with them
                String example = ( String ) map. get ( "exampleKey" ) ;

                return new ExampleObject ( ) ;
            }
        } ) ;


        // Example of Simply Serializing an object, it is that simple!
        ExampleObject object = new ExampleObject ( ) ;
        byte [ ] arr = Serializations. serialize (object ) ;
        ExampleObject deserializedObject = (ExampleObject ) Serializations. deserialize (arr ) ;

    }

}
 

import org.bukkit.persistence.PersistentDataAdapterContext ;
import org.bukkit.persistence.PersistentDataType ;
import org.bukkit.util.io.BukkitObjectInputStream ;
import org.bukkit.util.io.BukkitObjectOutputStream ;

import java.io.ByteArrayInputStream ;
import java.io.ByteArrayOutputStream ;

/**
* A PersistentDataType class which represents a byte[] data type since any object is first serialized to a byte[] through Serializations
*/
public class StoredData implements PersistentDataType < byte [ ] , byte [ ] > {


    public StoredData ( ) { }

    @Override
    public Class < byte [ ] > getComplexType ( ) {
        return byte [ ]. class ;
    }

    @Override
    public Class < byte [ ] > getPrimitiveType ( ) {
        return byte [ ]. class ;
    }

    @Override
    public byte [ ] toPrimitive ( byte [ ] arg0, PersistentDataAdapterContext arg1 ) {
        try {
            ByteArrayOutputStream byteOut = new ByteArrayOutputStream ( ) ;
            BukkitObjectOutputStream bukkitOut = new BukkitObjectOutputStream (byteOut ) ;
            bukkitOut. writeObject (arg0 ) ;
            bukkitOut. flush ( ) ;

            return byteOut. toByteArray ( ) ;

        } catch ( Exception e ) {
            e. printStackTrace ( ) ;
            return null ;
        }
    }
 
    @Override
    public byte [ ] fromPrimitive ( byte [ ] arg0, PersistentDataAdapterContext arg1 ) {
        try {
            ByteArrayInputStream byteIn = new ByteArrayInputStream (arg0 ) ;
            BukkitObjectInputStream bukkitIn = new BukkitObjectInputStream (byteIn ) ;

            return ( byte [ ] ) bukkitIn. readObject ( ) ;
        } catch ( Exception e ) {
            return null ;
        }

    }


}