How to interfere other windows program (with C#, C++ or Java)
<p>Sorry for the unclear title,but my english is not good enough to describes my question in one line.<br/></p>

<p><strong>For example</strong>, i have a udp gaming program called <strong>Garena</strong>,its halt user for 5s after every <br/>attemp to join room (by some client-code i guess),therefor i downloaded another program which called <strong>Garena Auto-joiner</strong>(C++) ,this program bypass 5sec waiting and attemp to join room every second,ultil succeed.<br/>
<strong>For example</strong> Warcraft III do not have manabar show on top of heroes(nomally just have Hpbar),but when i download <strong>Manabar</strong> and run it after in game, it even render a manabar below Hpbar<br/></p>

<p>What i want to ask is: "how can it do that?","is it related with cracking in anyway?","Can a Java program achieve similar use?".<br/>
Thank for your supports!</p>
