remove wasteful duplicate method calls

core/src/main/java/hudson/Plugin.java

@@ -227,8 +227,9 @@ public abstract class Plugin implements Saveable {
      */
     public void save() throws IOException {
         if(BulkChange.contains(this))   return;
-        getConfigXml().write(this);
-        SaveableListener.fireOnChange(this, getConfigXml());
+        XmlFile config = getConfigXml();
+        config.write(this);
+        SaveableListener.fireOnChange(this, config);
     }
 
     /**

core/src/main/java/hudson/PluginWrapper.java

@@ -485,9 +485,10 @@ public class PluginWrapper implements Comparable<PluginWrapper> {
      * or null if there's no back up.
      */
     public String getBackupVersion() {
-        if (getBackupFile().exists()) {
+        File backup = getBackupFile();
+        if (backup.exists()) {
             try {
-                JarFile backupPlugin = new JarFile(getBackupFile());
+                JarFile backupPlugin = new JarFile(backup);
                 return backupPlugin.getManifest().getMainAttributes().getValue("Plugin-Version");
             } catch (IOException e) {
                 LOGGER.log(WARNING, "Failed to get backup version ", e);

core/src/main/java/hudson/ProxyConfiguration.java

@@ -89,8 +89,9 @@ public final class ProxyConfiguration implements Saveable {
 
     public void save() throws IOException {
         if(BulkChange.contains(this))   return;
-        getXmlFile().write(this);
-        SaveableListener.fireOnChange(this, getXmlFile());
+        XmlFile config = getXmlFile();
+        config.write(this);
+        SaveableListener.fireOnChange(this, config);
     }
 
     public static XmlFile getXmlFile() {