test memory consumption of a java program with eclipse [closed]

问题

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Closed 6 years ago.

Is there a plugin in eclipse that I could use to test who much memory has my just run program cost?

I am thinking there may be a button from the plugin after I run the program, I could click on it, and it shows me a graph of sort of the peak memory consumption of my program just now.

回答1:

I personally like VisualVM (tutorial), included with the latest JDK releases.

回答2:

I agree with Mr. Nobody that VisualVM is nice. The Eclipse Memory Analyzer has some nice features as well.

回答3:

The total used / free memory of a program can be obtained in the program via java.lang.Runtime.getRuntime();

The runtime has several methods which relate to the memory. The following coding example demonstrates its usage.

import java.util.ArrayList;
import java.util.List;

public class PerformanceTest {
  private static final long MEGABYTE = 1024L * 1024L;

  public static long bytesToMegabytes(long bytes) {
    return bytes / MEGABYTE;
  }

  public static void main(String[] args) {
    // I assume you will know how to create an object Person yourself...
    List<Person> list = new ArrayList<Person>();
    for (int i = 0; i <= 100000; i++) {
      list.add(new Person("Jim", "Knopf"));
    }
    // Get the Java runtime
    Runtime runtime = Runtime.getRuntime();
    // Run the garbage collector
    runtime.gc();
    // Calculate the used memory
    long memory = runtime.totalMemory() - runtime.freeMemory();
    System.out.println("Used memory is bytes: " + memory);
    System.out.println("Used memory is megabytes: "
        + bytesToMegabytes(memory));
  }
} 

来源：https://stackoverflow.com/questions/5869432/test-memory-consumption-of-a-java-program-with-eclipse