How to get a caller class of a method

Question

How do I know which class called a method?

class A {
   B b = new B();

   public void methodA() {
    Class callerClass = b.getCallerCalss(); // it should b         


        

Answer 1

You can get the class name of the caller class by fetching the second element of the stack trace:

final StackTraceElement[] stackTrace = Thread.currentThread().getStackTrace();
System.out.println(stackTrace[1].getClassName());

The getClassName method of the StackTraceElement class returns with a String so you won't get a Class object unfortunately.

Answer 2

There's a method of observing the stacktrace

StackTraceElement[] elements = Thread.currentThread().getStackTrace()

Javadoc

The last element of the array represents the bottom of the stack, which is the least recent method invocation in the sequence.

Answer 3

This is easily done with Thread.currentThread().getStackTrace().

public static void main(String[] args) {
    doSomething();
}

private static void doSomething() {
    System.out.println(getCallerClass());
}

private static Class<?> getCallerClass() {
    final StackTraceElement[] stackTrace = Thread.currentThread().getStackTrace();
    String clazzName = stackTrace[3].getClassName();
    try {
        return Class.forName(clazzName);
    } catch (ClassNotFoundException e) {
        e.printStackTrace();
        return null;
    }
}

[3] is used because [0] is the element for Thread.currentThread(), [1] is for getCallerClass, [2] is for doSomething, and finally, [3] is main. If you put doSomething in another class, you'll see it returns the correct class.

Answer 4

Try Throwable.getStackTrace().

Create a new Throwable.. you don't have to throw it :).

untested:

Throwable t = new Throwable();
StackTraceElement[] es = t.getStackTrace();
// Not sure if es[0] would contain the caller, or es[1]. My guess is es[1].
System.out.println( es[0].getClass() + " or " + es[1].getClass() + " called me.");

Obviously if you're creating some function (getCaller()) then you'll have to go another level up in the stack trace.