[Java] object deep copy into different type

[chaokunyang]

Feature Request

We've supported object deep copy of object from one instance to another instance, but we still don't support deep copy object from one type into another type.

Is your feature request related to a problem? Please describe

deep copy object from one type into another type:

class Struct1 {
  int f1;
  String f2;

  public Struct1(int f1, String f2) {
    this.f1 = f1;
    this.f2 = f2;
  }
}

class Struct2 {
  int f1;
  String f2;
  double f3;
}

Struct1 s1 = xxx;
Struct2 struct2 = copyTo(s1, Struct2.class)

Describe the solution you'd like

Extend the current object deep copy mechanism

Describe alternatives you've considered

Mock by:

public class StructMappingExample {
  static class Struct1 {
    int f1;
    String f2;

    public Struct1(int f1, String f2) {
      this.f1 = f1;
      this.f2 = f2;
    }
  }

  static class Struct2 {
    int f1;
    String f2;
    double f3;
  }

  static ThreadSafeFury fury1 = Fury.builder()
    .withCompatibleMode(CompatibleMode.COMPATIBLE).buildThreadSafeFury();
  static ThreadSafeFury fury2 = Fury.builder()
    .withCompatibleMode(CompatibleMode.COMPATIBLE).buildThreadSafeFury();

  static {
    fury1.register(Struct1.class);
    fury2.register(Struct2.class);
  }

  public static void main(String[] args) {
    Struct1 struct1 = new Struct1(10, "abc");
    Struct2 struct2 = (Struct2) fury2.deserialize(fury1.serialize(struct1));
    Assert.assertEquals(struct2.f1, struct1.f1);
    Assert.assertEquals(struct2.f2, struct1.f2);
    struct1 = (Struct1) fury1.deserialize(fury2.serialize(struct2));
    Assert.assertEquals(struct1.f1, struct2.f1);
    Assert.assertEquals(struct1.f2, struct2.f2);
  }
}

This will work, but not that efficient cause it will write/read buffer.

Additional context

https://github.com/apache/fury/discussions/1973 https://github.com/apache/fury/pull/1974

[chaokunyang]

Hi @zhaommmmomo , would you like to take over this issue?