I tried your game from command line. Why is the frame rate so low? Only 40 FPS here. Could you use JOGL or LWJGL inside your game? It isn't an absolute necessity but it might improve the performance.
I fixed the Framerate to 40 fps....used... Thread.yeild();
code :
float target = 1000 / 40.0f;
float frameAverage = target;
long lastFrame = System.currentTimeMillis();
float yield = 1000f;
float damping = 0.1f;
long renderTime = 0;
long logicTime = 0;
while (gameRunning) {
long timeNow = System.currentTimeMillis();
frameAverage = (frameAverage * 10 + (timeNow - lastFrame)) / 11;
lastFrame = timeNow;
yield+=yield*((target/frameAverage)-1)*damping+0.05f;
for(int i=0;i<yield;i++) {
Thread.yield();
}
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