How to get the name of calling class that invoke given method?

Using SecurityManager#getClassContext we can get the name of calling class that invokes given method.

 

Signature

protected Class[] getClassContext()

Returns the current execution stack as an array of classes. The length of the array is the number of methods on the execution stack. The element at index 0 is the class of the currently executing method, the element at index 1 is the class of that method's caller, and so on.

 

Find the below working application.

 

StringUtil.java

package com.sample.app.util;

public class StringUtil {
    
    public static void printHi() {
        Class<?> clazz = AppUtil.getCallingClass();
        
        System.out.println("Hi!!!!!");
        System.out.println("This method is called by " + clazz);
    }

}

 

AppUtil.java

package com.sample.app.util;

public class AppUtil {

    private static ClassContextSecurityManager SECURITY_MANAGER;

    private static final class ClassContextSecurityManager extends SecurityManager {
        protected Class<?>[] getClassContext() {
            return super.getClassContext();
        }
    }

    private static ClassContextSecurityManager getSecurityManager() {

        if (SECURITY_MANAGER == null) {
            synchronized (AppUtil.class) {
                if (SECURITY_MANAGER == null) {
                    SECURITY_MANAGER = new ClassContextSecurityManager();
                }
            }
        }

        return SECURITY_MANAGER;
    }

    public static Class<?> getCallingClass() {
        ClassContextSecurityManager securityManager = getSecurityManager();
        if (securityManager == null)
            return null;
        Class<?>[] currentExecutionStack = securityManager.getClassContext();
        String currentClassName = AppUtil.class.getName();

        // Advance until AppUtil is found
        int i;
        for (i = 0; i < currentExecutionStack.length; i++) {
            if (currentClassName.equals(currentExecutionStack[i].getName()))
                break;
        }

        // currentExecutionStack[i] = AppUtil;
        // currentExecutionStack[i+1] = caller;
        // currentExecutionStack[i+2] = caller's caller
        if (i >= currentExecutionStack.length || i + 2 >= currentExecutionStack.length) {
            throw new IllegalStateException("Unable to get the name of calling class");
        }

        return currentExecutionStack[i + 2];
    }

}

App.java

package com.sample.app;

import com.sample.app.util.StringUtil;

public class App {
    
    public static void main(String[] args) {
        
        StringUtil.printHi();
    }

}

Output

Hi!!!!! This method is called by class com.sample.app.App

 

 

 

 

 

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