Blocker and Critical level bugfixes throughout the project (#4648)

* fixed https://sonarcloud.io/project/issues?id=org.xmage%3Amage-root&issues=AWIlv32RgrzAwlaaQ7rP&open=AWIlv32RgrzAwlaaQ7rP

* ensure closing of scanner if it was opened

* Refactored method in EmpyrialArchAngel to not always return same value.

* Refactored method in FalkenrathAristocrat to not always return same value.

* Refactored method in GilderBairn to not always return the same value.

* fixed left open resources, ensured quiet closing of the streams

* Refactored method in IceCave to not always return same value.

* Refactored method in KjeldoranRoyalGuard to not always return same value.

* Refactored method in LegionsInitiative to not always return same value.

* Refactored method in NaturesWill to not always return same value.

* added quiet closing method in new streamutils class, used to clean up the connectdialog

* Fix small typo

* added quiet closing to saveobjectutil

* closed resources in savegame method of gamecontroller

* properly close resources in loadGame method of GameReplay class

* further proper resource closing in ServerMessagesUtil

* fixed unclosed resources in copy method in mage framework Copier

* closed unclosed resources in copyCompressed method in Copier

* ensure closing of filewriter in manasymbols

* ensure proper closing of Stream in arcane UI

* ensure closing of datagram socket in arcane Util

* ensure resource closing in deckimport from clipboard

* ensure closing of plugin classloader

* ensured closing of zipinputstream resource

* ensure closing of fileoutputstream in ScryfallSymbolsSource

* ensure closing resources after finishing/canceling download of pictures

* remove commented code

* move locks to try block to ensure unlocking along all execution paths

* remove dangerous instance of double-checked locking

* removed dangerous instance of double checked locking in settingsmanager

* Removed dangerous instance of double-checked locking in ThemePluginImpl

* close resource which did not happen certainly

* close another stream

* ensure closing of inputstream

Mage/src/main/java/mage/util/Copier.java

@@ -50,36 +50,44 @@ public class Copier<T> {
 
     public T copy(T obj) {
         T copy = null;
+
+        FastByteArrayOutputStream fbos = null;
+        ObjectOutputStream out = null;
+        ObjectInputStream in = null;
         try {
-            FastByteArrayOutputStream fbos = new FastByteArrayOutputStream();
-            ObjectOutputStream out= new ObjectOutputStream(fbos);
+            fbos = new FastByteArrayOutputStream();
+            out = new ObjectOutputStream(fbos);
 
             // Write the object out to a byte array
             out.writeObject(obj);
             out.flush();
-            out.close();
 
             // Retrieve an input stream from the byte array and read
             // a copy of the object back in.
-            ObjectInputStream in = new CopierObjectInputStream(loader, fbos.getInputStream());
+            in = new CopierObjectInputStream(loader, fbos.getInputStream());
             copy = (T) in.readObject();
         }
         catch(IOException | ClassNotFoundException e) {
             e.printStackTrace();
+        } finally {
+            StreamUtils.closeQuietly(fbos);
+            StreamUtils.closeQuietly(out);
+            StreamUtils.closeQuietly(in);
         }
         return copy;
 
     }
 
     public byte[] copyCompressed(T obj) {
+        FastByteArrayOutputStream fbos = null;
+        ObjectOutputStream out = null;
         try {
-            FastByteArrayOutputStream fbos = new FastByteArrayOutputStream();
-            ObjectOutputStream out= new ObjectOutputStream(new GZIPOutputStream(fbos));
+            fbos = new FastByteArrayOutputStream();
+            out = new ObjectOutputStream(new GZIPOutputStream(fbos));
 
             // Write the object out to a byte array
             out.writeObject(obj);
             out.flush();
-            out.close();
 
             byte[] copy = new byte[fbos.getSize()];
             System.arraycopy(fbos.getByteArray(), 0, copy, 0, fbos.getSize());
@@ -87,6 +95,9 @@ public class Copier<T> {
         }
         catch(IOException e) {
             e.printStackTrace();
+        } finally {
+            StreamUtils.closeQuietly(fbos);
+            StreamUtils.closeQuietly(out);
         }
         return null;
     }

Mage/src/main/java/mage/util/StreamUtils.java

@@ -0,0 +1,30 @@
+package mage.util;
+
+import java.io.Closeable;
+
+public final class StreamUtils {
+
+    /***
+     * Quietly closes the closable, ignoring nulls and exceptions
+     * @param c - the closable to be closed
+     */
+    public static void closeQuietly(Closeable c) {
+        if (c != null) {
+            try {
+                c.close();
+            }
+            catch (Exception e) {
+            }
+        }
+    }
+
+    public static void closeQuietly(AutoCloseable ac) {
+        if (ac != null) {
+            try {
+                ac.close();
+            }
+            catch (Exception e) {
+            }
+        }
+    }
+}