Question

I was asked this by a fellow developer recently, and could not provide the answer…

In Java, how/when are variables disposed of? Are they?

Let’s say we have a run() method that gets called 50-75 times per second (heavily simplified example)…

public void run() {
    long lastTime = System.nanoTime();
    double unprocessed = 0;
    int ticks = 0;
    int frames = 0;
    double nsPerTick = 1000000000.0 / 60.0;
    long now = System.nanoTime();
    unprocessed += (now - lastTime) / nsPerTick;
    lastTime = now;

    ticks++;
    tick();
    unprocessed -= 1;
}

Would bringing those variables (lastTime, unprocessed, ticks, etc.) into a higher level of scope make the program run better/more efficiently–to a place where they are not created and used multiple times per second?

Answer 1

It won’t give you any performance improvement as those variables are created in stack.

Read this article to get more about Object destructions in Java:

What method in Java is used to destroy your objects