How can I release a method before execution the method using java

This is method that I call from view page:

public void methodA() {
    methodB();
    System.out.println("Complete");
}

public void methodB() {
    // some operation go here
    //it's execution time is minimum 5 min
}

My Question is : I want to release from methodB() before completing execution methodB() and I want to print "Complete" which is included in methodA();