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Author: AvinandanBose

AbstractCollectionDemo1.java

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+package TreeSet;
+
+import java.util.AbstractCollection;
+
+import java.util.HashSet;
+import java.util.TreeSet;
+import java.util.concurrent.CopyOnWriteArraySet;
+
+public class AbstractCollectionDemo1 {
+    AbstractCollection<Integer> demoCollection = new HashSet<>();
+    AbstractCollection<Integer> demoCollection1 = new TreeSet<>();
+    AbstractCollection<Integer> demoCollection2 = new CopyOnWriteArraySet<>();
+
+    public static void main(String[] args) {
+        AbstractCollectionDemo1 a = new AbstractCollectionDemo1();
+        a.demoCollection.add(1);
+        a.demoCollection.add(2);
+        a.demoCollection.add(3);
+        a.demoCollection.add(4);
+        System.out.println(a.demoCollection);
+    }
+}