set allowCoreThreadTimeOut for the ThreadPool, closeable

src/main/java/org/privacyidea/Endpoint.java

@@ -23,6 +23,7 @@
 import java.security.KeyManagementException;
 import java.security.NoSuchAlgorithmException;
 import java.util.Map;
+import java.util.concurrent.TimeUnit;
 import javax.net.ssl.SSLContext;
 import javax.net.ssl.SSLSocketFactory;
 import javax.net.ssl.TrustManager;

src/main/java/org/privacyidea/PrivacyIDEA.java

@@ -16,6 +16,8 @@
  */
 package org.privacyidea;
 
+import java.io.Closeable;
+import java.io.IOException;
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.LinkedHashMap;
@@ -26,7 +28,6 @@
 import java.util.concurrent.BlockingQueue;
 import java.util.concurrent.Callable;
 import java.util.concurrent.ExecutionException;
-import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Future;
 import java.util.concurrent.ThreadPoolExecutor;
 import java.util.concurrent.TimeUnit;
@@ -54,15 +55,15 @@
  * This is the main class. It implements the common endpoints such as /validate/check as methods for easy usage.
  * To create an instance of this class, use the nested PrivacyIDEA.Builder class.
  */
-public class PrivacyIDEA
+public class PrivacyIDEA implements Closeable
 {
     private final PIConfig configuration;
     private final IPILogger log;
     private final IPISimpleLogger simpleLog;
     private final Endpoint endpoint;
     // Thread pool for connections
-    private final BlockingQueue<Runnable> queue = new ArrayBlockingQueue<>(100);
-    private final ExecutorService threadPool = new ThreadPoolExecutor(20, 20, 10, TimeUnit.SECONDS, queue);
+    private final BlockingQueue<Runnable> queue = new ArrayBlockingQueue<>(1000);
+    private final ThreadPoolExecutor threadPool = new ThreadPoolExecutor(20, 20, 10, TimeUnit.SECONDS, queue);
     final JSONParser parser;
     // Responses from these endpoints will not be logged. The list can be overwritten.
     private List<String> logExcludedEndpoints = Arrays.asList(PIConstants.ENDPOINT_AUTH,
@@ -75,6 +76,7 @@ private PrivacyIDEA(PIConfig configuration, IPILogger logger, IPISimpleLogger si
         this.configuration = configuration;
         this.endpoint = new Endpoint(this);
         this.parser = new JSONParser(this);
+        this.threadPool.allowCoreThreadTimeOut(true);
     }
 
     /**
@@ -535,6 +537,12 @@ else if (this.simpleLog != null)
         }
     }
 
+    @Override
+    public void close() throws IOException
+    {
+        this.threadPool.shutdown();
+    }
+
     /**
      * Get a new Builder to create a PrivacyIDEA instance.
      *