Fix Port Binding Issue During Testing

src/test/java/com/oltpbenchmark/api/AbstractTestCase.java

@@ -39,6 +39,8 @@
 import java.util.ArrayList;
 import java.util.List;
 import java.util.concurrent.atomic.AtomicInteger;
+import java.net.ServerSocket;
+import java.net.BindException;
 
 public abstract class AbstractTestCase<T extends BenchmarkModule> {
 
@@ -69,6 +71,7 @@ public abstract class AbstractTestCase<T extends BenchmarkModule> {
     protected final String ddlOverridePath;
 
     private static final AtomicInteger portCounter = new AtomicInteger(9001);
+    private static final int MAX_PORT_NUMBER = 65535;
 
 
     public AbstractTestCase(boolean createDatabase, boolean loadDatabase) {
@@ -99,7 +102,7 @@ public final void setUp() throws Exception {
         HsqlProperties props = new HsqlProperties();
         //props.setProperty("server.remote_open", true);
 
-        int port = portCounter.incrementAndGet();
+        int port = findAvailablePort();
 
         LOG.info("starting HSQLDB server for test [{}] on port [{}]", name.getMethodName(), port);
 
@@ -163,6 +166,23 @@ public final void setUp() throws Exception {
         }
     }
 
+    private int findAvailablePort() throws IOException {
+        while (true) {
+            int port = portCounter.incrementAndGet();
+
+            if (port > MAX_PORT_NUMBER) {
+                throw new IOException("No available port found up to " + MAX_PORT_NUMBER);
+            }
+
+            try (ServerSocket testSocket = new ServerSocket(port)) {
+                return port;
+            } catch (BindException e) {
+                // This port is already in use. Continue to next port.
+                LOG.warn("Port {} is already in use. Trying next port.", port);
+            }
+        }
+    }
+
     protected TransactionTypes proceduresToTransactionTypes(List<Class<? extends Procedure>> procedures) {
         TransactionTypes txnTypes = new TransactionTypes(new ArrayList<>());