..

test/com/platform/test/SetTest.java

@@ -0,0 +1,25 @@
+package com.platform.test;
+
+import java.util.HashSet;
+import java.util.Set;
+
+import org.junit.Test;
+
+public class SetTest {
+	
+	@Test
+	public void testSet() {
+		Set<String> set = new HashSet<String>();
+		set.add("a");
+		set.add("a");
+		set.add("b");
+		set.add("c");
+		System.out.println(set.size());
+		set.remove("c");
+		System.out.println(set.size());
+		set.remove("a");
+		System.out.println(set.size());
+
+	}
+
+}