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Java Compiler compileClasses() method with example

Compiler Class compileClasses() method: Here, we are going to learn about the compileClasses() method of Compiler Class with its syntax and example.
Submitted by Preeti Jain, on December 02, 2019

Compiler Class compileClasses() method

• compileClasses() method is available in java.lang package.
• compileClasses() method is used to Compiles all the classes whose class name meets the given String parameter.
• compileClasses() method is a static method, it is accessible with the class name and if we try to access the method with the class object then we will not get any error.
• compileClasses() method may throw an exception at the time of compiling the classes.
  NullPointerException: This exception may throw when a given String parameter is null exists.

Syntax:

    public static boolean compileClasses(String str);

Parameter(s):

• String str – represents the name of the classes.

Return value:

The return type of this method is String, it returns the following values based on the given cases,

• It returns true when the given classes are compiled successfully.
• It returns false when the given classes are failed compilation or none compiler exists.

Example:

// Java program to demonstrate the example 
// of boolean compileClasses(String str) method of Compiler 

public class Parent {
    public static void main(String args[]) {
        String s = "Parent";

        // Creating a Parent and Child class object
        Parent p1 = new Parent();
        Parent p2 = new Child();

        // By using getClass() method is to get a Parent class
        Class cl1 = p1.getClass();
        System.out.println("p1.getClass() = " + cl1);

        // By using getClass() method is to get a Child class
        Class cl2 = p2.getClass();
        System.out.println("p2.getClass() = " + cl2);

        // By using compileClasses(String s) method is to compile 
        // Parent class it return boolean values if it returns true
        // then given class is compiled successfully otherwise 
        // compilation failed or no compiler exists
        boolean status = Compiler.compileClasses(s);
        System.out.println("Compiler.compileClasses(s) = " + status);
    }
}

class Child extends Parent {
    public void show() {
        System.out.println("We are in Child class: ");
    }
}

Output

p1.getClass() = class Parent
p2.getClass() = class Child
Compiler.compileClasses(s) = false