Java.lang.Compiler Class in Java

Difficulty Level : Medium
Last Updated : 27 Apr, 2017

Compiler Class provides support and related services to Java code to Native Code.
Native code is a form of code that can be said to run in a virtual machine (for example, [JVM]Java Virtual Machine).

Declaration :

public final class Compiler
   extends Object

Methods :

command() : java.lang.Compiler.command() tests the argument type and performs some documented operations.
Syntax :

public static boolean command(Object argument)
Parameters : 
argument : needs to be compiler specific.
Return  :
compiler specific value
Exception : 
-> NullPointerException

compileClass() : java.lang.Compiler.compileClass() compiles the specified class.
Syntax :
```
public static boolean compileClass(Class c)
Parameters : 
c : class to be compiled.
Return  :
 true if the compilation succeeded else, false
Exception : 
-> NullPointerException
```
enable() : java.lang.Compiler.enable() cause compiler to start operation.
Syntax :
```
public static void enable()
Parameters : 
------
Return  :
void
```
disable() : java.lang.Compiler.disable() stops compiler to perform operations.
Syntax :
```
public static void disable()
Parameters : 
-------
Return  :
void
```

compileClasses() : java.lang.Compiler.compileClasses() compiles the classes having the name as string – “str”
Syntax :

public static boolean compileClasses(String string)
Parameters : 
str : name of the class to be compiled
Return  :
true if the classes are compiled successfully 
Exception : 
-> NullPointerException

// Java Program illustrating the use of Compiler class Methods.
  
import java.lang.*;
  
public class NewClass
{
    public static void main(String[] args)
    {
        CompilerClass geek = new CompilerClass();
  
        // Use of enable() :
        Compiler.enable();
  
        // class CompilerDemo
        Class c = geek.getClass();
        System.out.println(c);
  
        // Use of command() :
        Object g = Compiler.command("javac CompilerClass");
        System.out.println("Value : " + g);
  
        // Use of compileClass :
        // Since it is not a subclass so there is no compiler for it
        boolean check = Compiler.compileClass(c);
        System.out.println("\nIs compilation successful ? : " + check);
  
        String str = "CompilerClass";
        boolean check1 = Compiler.compileClasses(str);
  
        System.out.println("\nIs compilation successful using str ? : " + check1);
  
        // Use of disable() :
        Compiler.disable();
    }
  
    private static class CompilerClass
    {
        public CompilerClass()
        {
        }
    }
}

Output :

class NewClass$CompilerClass
Value : null

Is compilation successful ? : false

Is compilation successful using str ? : false

Note :
lang.Compiler Class inherits others methods from Object class in Java.

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