The following prints the current caller class. Note that in this case, the [StackWalker](<http://download.java.net/java/jdk9/docs/api/java/lang/StackWalker.html>) needs to be created with the option [RETAIN_CLASS_REFERENCE](<http://download.java.net/java/jdk9/docs/api/java/lang/StackWalker.Option.html#RETAIN_CLASS_REFERENCE>), so that Class instances are retained in the [StackFrame](<http://download.java.net/java/jdk9/docs/api/java/lang/StackWalker.StackFrame.html>) objects. Otherwise an exception would occur.

public class StackWalkerExample {

    public static void main(String[] args) {
        FooHelper.foo();
    }

}

class FooHelper {
    protected static void foo() {
        BarHelper.bar();
    }
}

class BarHelper {
    protected static void bar() {
        System.out.println(StackWalker.getInstance(Option.RETAIN_CLASS_REFERENCE).getCallerClass());
    }
}

Output:

class test.FooHelper