Execute a function "before each" method of the same class in java

Lets make a method turnBooleanTrue() where effectively the boolean is set to true in order for the method to be execute correctly.

Then, you can write up your very own InvocationHandler that would intercept calls to your objects, and then reflectively (using reflection API) invoke first the turnBooleanTrue() method followed by the method to which the call was made.

Will look something like this

public class MyClassInvocationHandler implements InvocationHandler {

    // initiate an instance of the class
    MyClass myClass = new MyClassImpl();

    @Override
    public Object invoke(Object proxy, Method method, Object[] args)
            throws Throwable {

        // look up turnBooleanTrue() method
        Method turnBooleanTrue = myClass.getClass().getMethod("turnBooleanTrue");

        // invoke the method
        turnBooleanTrue.invoke(...); // toggle the boolean

        // invoke the method to which the call was made
        // pass in instance of class
        Object returnObj = method.invoke(myClass, args);

        return returnObj;
}

EDIT

Added some lines to have an object of MyClass initialized. You need something to invoke the method on and maintain the state. Changed util to myClass in the code example above.