Java compiler

A Java compiler is a compiler for the programming language Java. The most common form of output from a Java compiler is Java class files containing platform-neutral Java bytecode, but there are also compilers that output optimized native machine code for a particular hardware/operating system combination.

Most Java-to-bytecode compilers, Jikes being a well known exception, do virtually no optimization, leaving this until run time to be done by the JRE.

The Java virtual machine (JVM) loads the class files and either interprets the bytecode or just-in-time compiles it to machine code and then possibly optimizes it using dynamic compilation.

A standard on how to interact with Java compilers programmatically was specified in JSR 199.

import java.util.Scanner;

class secondmax {
     public static void main (String args[]) {
               int n,temp,fmax=0,smax=0;
               Scanner sc=new Scanner(System.in);
               System.out.println("Enter how many numbers will you enter:");
               n=sc.nextInt();
               for(int i=0; i<n; i++) {
                    temp=sc.nextInt();
                    if(i == 0) {
                       fmax=temp;
                    } else if(temp > fmax) {
                       fmax=temp;
                    }
               }
            
            System.out.println("First max: " + fmax);  
            System.out.println("Second max: " + smax);  
     }           
}

External links

• Sun's OpenJDK javac page
• JSR 199 Java Compiler API Java Specification Request for invoking the Java compiler from a Java program
• Stephan Diehl, "A Formal Introduction to the Compilation of Java", Software - Practice and Experience, Vol. 28(3), pages 297-327, March 1998.