bond java possible deadlock when create class and inner class at the same time

[Zhuoqing]

This is probably by design. StructBondType is sharing global lock across all bond class, while JVM will take Class lock for clinit class. So when ClassOut and ClassIn are being created in different thread, deadlock could possible happen when
ClassOut clinit take the StructBondType lock, trying to create ClassIn and wait for ClassIn clinit lock,

while ClassIn take the clinit lock, while wait for StructBondType lock

The workaround we did is simply pre-init those classes.

Bond file

namespace TestBondClassLock

struct ClassIn
{
    1: int32 InField;
}

struct ClassOut
{
	1: ClassIn InClass;
}

Test program

import TestBondClassLock.ClassIn;
import TestBondClassLock.ClassOut;

public class Main {

    public static void main(String[] args) {

        System.out.println("Creating Thread...");
        Thread thread1 = new Thread(() -> {
            System.out.println("outClass creating : " + Thread.currentThread().getName());
            ClassOut classOut = new ClassOut();
            System.out.println("outClass created : " + classOut.toString() + Thread.currentThread().getName());
        }, "ClassOutCreateThread");
        Thread thread2 = new Thread(() -> {
            System.out.println("ClassIn creating : " + Thread.currentThread().getName());
            ClassIn classIn = new ClassIn();
            System.out.println("ClassIn created : " + classIn.toString() + Thread.currentThread().getName());
        }, "ClassInCreateThread");

        thread1.start();
        thread2.start();
        try {
            thread1.join();
            thread2.join();
        }
        catch (InterruptedException ie) {
            System.out.println("InterruptedException:" + ie.getMessage() + ie.getStackTrace());
        }
        System.out.println("Finish!");
    }
}