diff --git a/代码/workspace_robo4/plugins/dotnet/robocode.dotnet.installer/src/main/java/net/sf/robocode/installer/AutoExtract.java b/代码/workspace_robo4/plugins/dotnet/robocode.dotnet.installer/src/main/java/net/sf/robocode/installer/AutoExtract.java
index b191f9b..9ebdb61 100644
--- a/代码/workspace_robo4/plugins/dotnet/robocode.dotnet.installer/src/main/java/net/sf/robocode/installer/AutoExtract.java
+++ b/代码/workspace_robo4/plugins/dotnet/robocode.dotnet.installer/src/main/java/net/sf/robocode/installer/AutoExtract.java
@@ -9,6 +9,7 @@ package net.sf.robocode.installer;
 
 
 import javax.swing.*;
+
 import java.awt.*;
 import java.awt.event.ActionEvent;
 import java.awt.event.ActionListener;
@@ -33,18 +34,19 @@ public class AutoExtract implements ActionListener {
 	private static File installDir;
 	private static final String javaVersion = System.getProperty("java.version");
 
-	private boolean acceptLicense() {
+	private boolean acceptLicense() throws IOException {
 		String licenseText = "";
 
 		InputStream is;
 
+		JarFile extractJar = null;
 		try {
-			JarFile extractJar = new JarFile("extract.jar");
+			extractJar = new JarFile("extract.jar");
 
 			is = extractJar.getInputStream(extractJar.getJarEntry("license/cpl-v10.html"));
 		} catch (IOException e) {
 			return true;
-		}finally{
+		} finally{
 			extractJar.close();
 		}
 		if (is == null) {
@@ -227,7 +229,7 @@ public class AutoExtract implements ActionListener {
 		}
 	}
 
-	public static void main(String argv[]) {
+	public static void main(String argv[]) throws HeadlessException, IOException {
 		// Verify that the Java version is version 6 (1.6.0) or newer
 		if (javaVersion.startsWith("1.") && javaVersion.charAt(2) < '5') {
 			final String message = "Robocode requires Java 6 (1.6.0) or newer.\n"
@@ -242,7 +244,7 @@ public class AutoExtract implements ActionListener {
 		// Set native look and feel
 		try {
 			UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
-		} catch (RuntimeException t) {// For some reason Ubuntu 7 can cause a NullPointerException when trying to getting the LAF
+		} catch (Throwable t) {// For some reason Ubuntu 7 can cause a NullPointerException when trying to getting the LAF
 		}
 
 		File suggestedDir;