InheritableThreadLocal sample code

The following code print null. If using InheritableThreadLocal, it print main.

 

 

class A {
  //static ThreadLocal local = new InheritableThreadLocal();
  static ThreadLocal local = new ThreadLocal();
}

public class Sample {
  public static void main (String [] args) {
    A.local.set("main");    
    Thread t = new Thread() {
      @Override
      public void run() {
        System.out.println(A.local.get());  
      }
    };
    t.start();
  }  
}

  The following code shows the usage of childValue method.

 

class A {
  static ThreadLocal<String> local = new InheritableThreadLocal<String>() {
    @Override
    protected String childValue(String parentValue) {
      return "child: " + parentValue;
    }
  };
}

public class Sample {
  public static void main (String [] args) {
    A.local.set("main");    
    Thread t = new Thread() {
      @Override
      public void run() {
        System.out.println(A.local.get());  
      }
    };
    t.start();
  }  
}