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.
I personally like VisualVM (tutorial), included with the latest JDK releases.
I agree with Mr. Nobody that VisualVM is nice. The Eclipse Memory Analyzer has some nice features as well.
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));
}
}
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