JVM Memory

Tanglong9344 · Jan 11, 2018 · fdb81c4 · fdb81c4
1 parent a6b0406
commit fdb81c4
Showing 1 changed file with 31 additions and 0 deletions.
diff --git a/src/java_core_basic/JVMMemory.java b/src/java_core_basic/JVMMemory.java
@@ -0,0 +1,31 @@
+package java_core_basic;
+
+/**
+ * The memory of JVM
+ *
+ * @author ÌÆÁú
+ *
+ */
+public class JVMMemory {
+	public static void main(String[] args) {
+		final int M = 1024*1024;
+		long maxMemory       = Runtime.getRuntime().maxMemory()/M;
+		long totalUsedMemory = Runtime.getRuntime().totalMemory()/M;
+		System.out.println("MaxMemory      : " + maxMemory + "M");
+		System.out.println("TotalUsedMemory: " + totalUsedMemory + "M");
+
+		String s = "";
+		for(int i=0;i<10000;i++){
+			s += i;
+		}
+		System.out.println(s);
+		totalUsedMemory = Runtime.getRuntime().totalMemory()/M;
+		System.out.println("TotalUsedMemory: " + totalUsedMemory + "M");
+
+		for(int i=0;i<10000_0000;i++){
+			new String("" + i);
+		}
+		totalUsedMemory = Runtime.getRuntime().totalMemory()/M;
+		System.out.println("TotalUsedMemory: " + totalUsedMemory + "M");
+	}
+}