diff --git a/代码/workspace_robo4/robocode.installer/src/main/java/net/sf/robocode/installer/AutoExtract.java b/代码/workspace_robo4/robocode.installer/src/main/java/net/sf/robocode/installer/AutoExtract.java
index 247c69b..b872719 100644
--- a/代码/workspace_robo4/robocode.installer/src/main/java/net/sf/robocode/installer/AutoExtract.java
+++ b/代码/workspace_robo4/robocode.installer/src/main/java/net/sf/robocode/installer/AutoExtract.java
@@ -609,6 +609,7 @@ public class AutoExtract implements ActionListener {
 		} catch (IOException e) {
 			e.printStackTrace();
 		} finally {
+            if(out!=null)
 				out.close();
 			if (file != null) {
 				if (!file.delete()) {
diff --git a/代码/workspace_robo4/robocode.repository/src/main/java/net/sf/robocode/repository/root/BaseRoot.java b/代码/workspace_robo4/robocode.repository/src/main/java/net/sf/robocode/repository/root/BaseRoot.java
index 14b6c89..6221701 100644
--- a/代码/workspace_robo4/robocode.repository/src/main/java/net/sf/robocode/repository/root/BaseRoot.java
+++ b/代码/workspace_robo4/robocode.repository/src/main/java/net/sf/robocode/repository/root/BaseRoot.java
@@ -61,7 +61,7 @@ public abstract class BaseRoot implements Serializable, IRepositoryRoot {
 	public void extractJAR() {
 		throw new UnsupportedOperationException();
 	}
-
+    @Override
 	public boolean equals(Object obj) {
 		if (obj instanceof IRepositoryRoot) {
 			return ((IRepositoryRoot) obj).getURL().equals(rootURL);
diff --git a/代码/workspace_robo4/robocode.roborumble/src/main/java/net/sf/robocode/roborumble/battlesengine/BattlesRunner.java b/代码/workspace_robo4/robocode.roborumble/src/main/java/net/sf/robocode/roborumble/battlesengine/BattlesRunner.java
index 13cbd64..78a2c22 100644
--- a/代码/workspace_robo4/robocode.roborumble/src/main/java/net/sf/robocode/roborumble/battlesengine/BattlesRunner.java
+++ b/代码/workspace_robo4/robocode.roborumble/src/main/java/net/sf/robocode/roborumble/battlesengine/BattlesRunner.java
@@ -109,7 +109,7 @@ public class BattlesRunner {
 
 					lastResults = null;
 					engine.runBattle(specification, true);
-					if (lastResults != null && lastResults.length > 1) {
+					if (lastResults.length > 1) {
 						dumpResults(outtxt, lastResults, param[param.length - 1], melee);
 					}
 				}
@@ -157,11 +157,10 @@ public class BattlesRunner {
 		try {
 			FileReader fr = new FileReader(inputfile);
 			br = new BufferedReader(fr);
-
+			fr.close();
 			String record;
 			while ((record = br.readLine()) != null) {
 				robots.add(record);
-			fr.close();
 			}
 		} catch (IOException e) {
 			System.out.println("Battles input file not found ... Aborting");
diff --git a/代码/workspace_robo4/robocode.roborumble/src/main/java/net/sf/robocode/roborumble/battlesengine/PrepareBattles.java b/代码/workspace_robo4/robocode.roborumble/src/main/java/net/sf/robocode/roborumble/battlesengine/PrepareBattles.java
index a2a30ca..5043562 100644
--- a/代码/workspace_robo4/robocode.roborumble/src/main/java/net/sf/robocode/roborumble/battlesengine/PrepareBattles.java
+++ b/代码/workspace_robo4/robocode.roborumble/src/main/java/net/sf/robocode/roborumble/battlesengine/PrepareBattles.java
@@ -425,6 +425,7 @@ public class PrepareBattles {
 					}
 				}
 			}
+			fr.close();
 		} catch (IOException e) {
 			System.out.println("Participants file not found ... Aborting");
 			System.out.println(e);
diff --git a/代码/workspace_robo4/robocode.roborumble/src/main/java/net/sf/robocode/roborumble/netengine/BotsDownload.java b/代码/workspace_robo4/robocode.roborumble/src/main/java/net/sf/robocode/roborumble/netengine/BotsDownload.java
index d29b50b..78d5920 100644
--- a/代码/workspace_robo4/robocode.roborumble/src/main/java/net/sf/robocode/roborumble/netengine/BotsDownload.java
+++ b/代码/workspace_robo4/robocode.roborumble/src/main/java/net/sf/robocode/roborumble/netengine/BotsDownload.java
@@ -392,7 +392,7 @@ public class BotsDownload {
 			InputStream properties = jarf.getInputStream(zipe);
 
 			Properties parameters = getProperties(properties);
-
+			jarf.close();
 			if (!isteams.equals("YES")) {
 				String classname = parameters.getProperty("robot.classname", "");
 				String version = parameters.getProperty("robot.version", "");
@@ -402,7 +402,7 @@ public class BotsDownload {
 			String version = parameters.getProperty("team.version", "");
 
 			return (botname.equals(botname.substring(0, botname.indexOf(" ")) + " " + version));
-			jarf.close();
+			
 		} catch (Exception e) {
 			System.out.println(e);
 			return false;
diff --git a/代码/workspace_robo4/robocode.tests/src/test/java/net/sf/robocode/test/core/util/AlphanumericComparatorTest.java b/代码/workspace_robo4/robocode.tests/src/test/java/net/sf/robocode/test/core/util/AlphanumericComparatorTest.java
index 255fbd2..828ded7 100644
--- a/代码/workspace_robo4/robocode.tests/src/test/java/net/sf/robocode/test/core/util/AlphanumericComparatorTest.java
+++ b/代码/workspace_robo4/robocode.tests/src/test/java/net/sf/robocode/test/core/util/AlphanumericComparatorTest.java
@@ -50,7 +50,7 @@ public class AlphanumericComparatorTest {
 			String str1 = unsortedStrings[i];
 			String str2 = correctlySortedStrings[i];
 			
-			if (!(str1 == null && str2 == null) && !str1.equals(str2)) {
+			if (str1!=null&&!(str1 == null && str2 == null) && !str1.equals(str2)) {
 				sortedCorrectly = false;
 				break;
 			}
diff --git a/代码/workspace_robo4/robocode.ui.editor/src/main/java/net/sf/robocode/ui/editor/JavaDocument.java b/代码/workspace_robo4/robocode.ui.editor/src/main/java/net/sf/robocode/ui/editor/JavaDocument.java
index 7497f42..d3fd266 100644
--- a/代码/workspace_robo4/robocode.ui.editor/src/main/java/net/sf/robocode/ui/editor/JavaDocument.java
+++ b/代码/workspace_robo4/robocode.ui.editor/src/main/java/net/sf/robocode/ui/editor/JavaDocument.java
@@ -484,6 +484,7 @@ public class JavaDocument extends StyledDocument {
 			spaceBuffer = new String(chars);
 		}
 		// Return a string containing the given number of spaces
+        if(spaceBuffer!=null)
 		return spaceBuffer.substring(0, count);
 	}
 
diff --git a/代码/workspace_robo4/robocode.ui/src/main/java/net/sf/robocode/ui/dialog/PreferencesSoundOptionsTab.java b/代码/workspace_robo4/robocode.ui/src/main/java/net/sf/robocode/ui/dialog/PreferencesSoundOptionsTab.java
index 1653e10..d642d20 100644
--- a/代码/workspace_robo4/robocode.ui/src/main/java/net/sf/robocode/ui/dialog/PreferencesSoundOptionsTab.java
+++ b/代码/workspace_robo4/robocode.ui/src/main/java/net/sf/robocode/ui/dialog/PreferencesSoundOptionsTab.java
@@ -227,8 +227,9 @@ public class PreferencesSoundOptionsTab extends WizardPanel {
 			for (Mixer.Info mi : mixerInfo) {
 				if (AudioSystem.getMixer(mi).getSourceLineInfo(clipLineInfo).length > 0) {
 					mixers.add(mi);
+                    AudioSystem.getMixer(mi).close();
 				}
-				AudioSystem.getMixer(mi).close();
+				
 			}
 
 			mixerComboBox = new JComboBox(mixers);
@@ -297,9 +298,8 @@ public class PreferencesSoundOptionsTab extends WizardPanel {
 		if (mixerInfo != null) {
 			Mixer mixer = AudioSystem.getMixer((Mixer.Info) getMixerComboBox().getSelectedItem());
 
-			if (mixer != null) {
 				mixerClassName = mixer.getClass().getSimpleName();
-			}
+			
 		}
 		if (mixerClassName != null) {
 			props.setOptionsSoundMixer(mixerClassName);
@@ -317,9 +317,10 @@ public class PreferencesSoundOptionsTab extends WizardPanel {
 		for (Mixer.Info mi : AudioSystem.getMixerInfo()) {
 			if (AudioSystem.getMixer(mi).getClass().getSimpleName().equals(mixerName)) {
 				getMixerComboBox().setSelectedItem(mi);
+                AudioSystem.getMixer(mi).close();
 				break;
 			}
-			AudioSystem.getMixer(mi).close();
+			
 		}
 	}