1 reply to this topic

[ReignInChaos]

After having a discussion with a co-worker, we were in disagreement on if the Java compiler "compiles out" unnecessary code. I have heard rumors that C compilers do this during preprocessing, but I have not found any documentation that agrees or disagrees with these statements. If anyone has heard similar statements or better yet has some form of documentation that proves/disproves the above, please reply.

For example, some say that

doSomething();

if ( false )
{
  ...
}

doSomethingElse();

would get compiled into

doSomething();

doSomethingElse();

Any thoughts???

[wim DC]

Class I made:

/**
 * User: wimDC Date: 9/11/11 Time: 15:26
 */
public class Test
{
    public void anything(String unused){
        if(false){
            System.out.println("never printed.");
        }
    }
}

Compiled, and then decompiled it:

/* Decompiled through IntelliJad */
// Decompiled by Jad v1.5.8g. Copyright 2001 Pavel Kouznetsov.
// Jad home page: http://www.kpdus.com/jad.html
// Decompiler options: packfields(3) packimports(3) splitstr(64) radix(10) lradix(10) 
// Source File Name:   Test.java

public class Test
{


    public Test()
    {
    }


    public void anything(String s)
    {
    }
}

Edit: you also can't debug that part, it just skips it.

Edited by wim DC, 10 November 2011 - 07:46 AM.