You can invoke or call a method from another program or method.

When you want to use an access method services function, enter a command and specify its parameters. Your request is decoded one command at a time; the appropriate functional routines perform all services required by that command.

You can call the access method services program:

• As a job or jobstep
• From a TSO/E session
• From within your own program

You can run the IDCAMS program [the access method services operating system] and include the command and its parameters as input to the program. You can also call the IDCAMS program from within another program and pass the command and its parameters to the IDCAMS program.

Time sharing option [TSO/E] users can run access method services functional commands from a TSO/E session as though they were TSO/E commands.

You can call the private method from outside the class by changing the runtime behaviour of the class.

With the help of java.lang.Class class and java.lang.reflect.Method class, we can call a private method from any other class.

Required methods of Method class

1] public void setAccessible[boolean status] throws SecurityException sets the accessibility of the method.

2] public Object invoke[Object method, Object... args] throws IllegalAccessException, IllegalArgumentException, InvocationTargetException is used to invoke the method.

Required method of Class class

1] public Method getDeclaredMethod[String name,Class[] parameterTypes]throws NoSuchMethodException,SecurityException: returns a Method object that reflects the specified declared method of the class or interface represented by this Class object.

Example of calling private method from another class

Let's see the simple example to call private method from another class.

File: A.java

File: MethodCall.java

Output:

Another example to call parameterized private method from another class

Let's see the example to call parameterized private method from another class

File: A.java

File: M.java

Output:

Accessing Private Constructors of a class

We know that constructors of a class are a special kind of method this is used to instantiate the class. To access the private constructor, we use the method getDeclaredConstructor[]. The getDeclaredConstructor[] is used to access a parameterless as well as a parametrized constructor of a class. The following example shows the same.

In this article, we will understand how to pass method call as arguments to another method. We can call a method from another class by just creating an object of that class inside another class. After creating an object, call methods using the object reference variable.

Below is a demonstration of the same −

Input

Suppose our input is −

Enter two numbers : 2 and 3

Output

The desired output would be −

The cube of the sum of two numbers is:
125

Algorithm

Step 1 - START
Step 2 - Declare two variables values namely my_input_1 and my_input_2
Step 3 - We define a function that takes two numbers, and returns their sum.
Step 4 - We define another function that takes one argument and multiplies it thrice, and returns the output.
Step 5 - In the main function, we create a new object of the class, and create a Scanner object.
Step 6 - Now, we can either pre-define the number or prompt the user to enter it.
Step 7 - Once we have the inputs in place, we invoke the function that returns the cube of the input.
Step 8 - This result is displayed on the console.

Example 1

Here, the input is being entered by the user based on a prompt. You can try this example live in ourcoding ground tool

import java.util.Scanner;
public class Main {
   public int my_sum[int a, int b] {
      int sum = a + b;
      return sum;
   }
   public void my_cube[int my_input] {
      int my_result = my_input * my_input * my_input;
      System.out.println[my_result];
   }
   public static void main[String[] args] {
      Main obj = new Main[];
      int my_input_1, my_input_2;
      System.out.println["Required packages have been imported"];
      Scanner my_scanner = new Scanner[System.in];
      System.out.println["A reader object has been defined "];
      System.out.print["Enter the first number : "];
      my_input_1 = my_scanner.nextInt[];
      System.out.print["Enter the second number : "];
      my_input_2 = my_scanner.nextInt[];
      System.out.println["The cube of the sum of two numbers is: "];
      obj.my_cube[obj.my_sum[my_input_1, my_input_2]];
   }
}

Output

Required packages have been imported
A reader object has been defined
Enter the first number : 2
Enter the second number : 3
The cube of the sum of two numbers is:
125

Example 2

Here, the integer has been previously defined, and its value is accessed and displayed on the console.

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