diff --git a/ConnectionPoolTest.java b/ConnectionPoolTest.java
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+++ b/ConnectionPoolTest.java
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+
+
+/**
+ * Test class: Verify object pool manager functionality
+ * @author chuyang
+ * @version 1.0
+ */
+public class ConnectionPoolTest {
+
+	public ConnectionPoolManager m_ConnectionPoolManager;
+
+	public ConnectionPoolTest(){
+
+	}
+
+	@Override
+	public void finalize() throws Throwable {
+
+	}
+	/**
+	 * Main test method
+	 * @param args
+	 */
+	public static void main(String[] args) {
+		System.out.println("=== Start Object Pool Manager Test ===");
+		
+		// 1. Test initializing connection pool
+		System.out.println("\n1. Initialize connection pool");
+		ConnectionPoolManager poolManager = new ConnectionPoolManager(2, 5, "jdbc:mysql://localhost:3306/testdb");
+		System.out.println(poolManager.getPoolStatus());
+		
+		// 2. Test borrowing connections
+		System.out.println("\n2. Test borrowing connections");
+		DatabaseConnection conn1 = poolManager.borrowConnection();
+		DatabaseConnection conn2 = poolManager.borrowConnection();
+		DatabaseConnection conn3 = poolManager.borrowConnection(); // Should create new connection
+		System.out.println(poolManager.getPoolStatus());
+		
+		// 3. Test returning connections
+		System.out.println("\n3. Test returning connections");
+		poolManager.returnConnection(conn1);
+		System.out.println(poolManager.getPoolStatus());
+		
+		// 4. Test reusing connections
+		System.out.println("\n4. Test reusing connections");
+		DatabaseConnection conn4 = poolManager.borrowConnection(); // Should reuse just returned connection
+		System.out.println("Reused connection ID: " + conn4.getConnectionId());
+		System.out.println(poolManager.getPoolStatus());
+		
+		// 5. Test pool full condition
+		System.out.println("\n5. Test pool full condition");
+		DatabaseConnection conn5 = poolManager.borrowConnection(); // Create 4th connection
+		DatabaseConnection conn6 = poolManager.borrowConnection(); // Create 5th connection (reach max capacity)
+		DatabaseConnection conn7 = poolManager.borrowConnection(); // Should return null as pool is full
+		System.out.println("Result of borrowing beyond max capacity: " + (conn7 == null ? "Pool is full, cannot borrow more connections" : "Successfully borrowed connection"));
+		System.out.println(poolManager.getPoolStatus());
+		
+		// 6. Test shrinking pool
+		System.out.println("\n6. Test shrinking pool");
+		// Return some connections for shrinking
+		poolManager.returnConnection(conn2);
+		poolManager.returnConnection(conn3);
+		poolManager.returnConnection(conn5);
+		poolManager.returnConnection(conn6);
+		System.out.println("Before shrink " + poolManager.getPoolStatus());
+		poolManager.shrinkPool();
+		System.out.println("After shrink " + poolManager.getPoolStatus());
+		
+		// 7. Test thread safety (simple test)
+		System.out.println("\n7. Simple thread safety test");
+		ConnectionPoolManager threadTestPool = new ConnectionPoolManager(3, 10, "jdbc:mysql://localhost:3306/testdb");
+		
+		// Create several threads to borrow and return connections simultaneously
+		Thread[] threads = new Thread[5];
+		for (int i = 0; i < threads.length; i++) {
+			final int threadId = i;
+			threads[i] = new Thread(() -> {
+				try {
+					System.out.println("Thread " + threadId + " borrowing connection");
+					DatabaseConnection conn = threadTestPool.borrowConnection();
+					if (conn != null) {
+						System.out.println("Thread " + threadId + " got connection: " + conn.getConnectionId());
+						// Simulate using connection
+						Thread.sleep(200);
+						threadTestPool.returnConnection(conn);
+						System.out.println("Thread " + threadId + " returned connection: " + conn.getConnectionId());
+					}
+				} catch (Exception e) {
+					e.printStackTrace();
+				}
+			});
+			threads[i].start();
+		}
+		
+		// Wait for all threads to complete
+		for (Thread thread : threads) {
+			try {
+				thread.join();
+			} catch (InterruptedException e) {
+				Thread.currentThread().interrupt();
+			}
+		}
+		
+		System.out.println("\nAfter thread test " + threadTestPool.getPoolStatus());
+		
+		// 8. Test DatabaseConnection clone functionality
+		System.out.println("\n8. Test connection clone functionality");
+		DatabaseConnection originalConn = new DatabaseConnection("original-clone-test", "jdbc:mysql://localhost:3306/clonedb");
+		DatabaseConnection clonedConn = originalConn.clone();
+		System.out.println("Original connection ID: " + originalConn.getConnectionId());
+		System.out.println("Cloned connection ID: " + clonedConn.getConnectionId());
+		System.out.println("Cloned connection URL: " + clonedConn.getDatabaseUrl());
+		
+		System.out.println("\n=== Object Pool Manager Test Completed ===");
+	}
+}
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