Use char notation to represent a character to improve performance.

src/main/org/apache/tools/ant/AntClassLoader.java

@@ -495,7 +495,7 @@ protected void addPathFile(final File pathComponent) throws IOException {
         }
 
         final String absPathPlusTimeAndLength = pathComponent.getAbsolutePath()
-                + pathComponent.lastModified() + "-" + pathComponent.length();
+                + pathComponent.lastModified() + '-' + pathComponent.length();
         String classpath = pathMap.get(absPathPlusTimeAndLength);
         if (classpath == null) {
             try (JarFile jarFile = new JarFile(pathComponent)) {
@@ -1232,7 +1232,7 @@ private Certificate[] getCertificates(final File container, final String entry)
      * @param manifest the jar's manifest
      */
     protected void definePackage(final File container, final String packageName, final Manifest manifest) {
-        final String sectionName = packageName.replace('.', '/') + "/";
+        final String sectionName = packageName.replace('.', '/') + '/';
 
         String specificationTitle = null;
         String specificationVendor = null;
@@ -1368,7 +1368,7 @@ private Class<?> findClassInComponents(final String name)
             try {
                 stream = getResourceStream(pathComponent, classFilename);
                 if (stream != null) {
-                    log("Loaded from " + pathComponent + " "
+                    log("Loaded from " + pathComponent + ' '
                         + classFilename, Project.MSG_DEBUG);
                     return getClassFromStream(stream, name, pathComponent);
                 }
@@ -1377,7 +1377,7 @@ private Class<?> findClassInComponents(final String name)
             } catch (final IOException ioe) {
                 // ioe.printStackTrace();
                 log("Exception reading component " + pathComponent + " (reason: "
-                    + ioe.getMessage() + ")", Project.MSG_VERBOSE);
+                    + ioe.getMessage() + ')', Project.MSG_VERBOSE);
             } finally {
                 FileUtils.close(stream);
             }
@@ -1539,7 +1539,7 @@ public void addJavaLibraries() {
      */
     @Override
     public String toString() {
-        return "AntClassLoader[" + getClasspath() + "]";
+        return "AntClassLoader[" + getClasspath() + ']';
     }
 
     /** {@inheritDoc} */

src/main/org/apache/tools/ant/ArgumentProcessorRegistry.java

@@ -92,7 +92,7 @@ private void collectArgumentProcessors() {
         } catch (Exception e) {
             System.err.println("Unable to load ArgumentProcessor from service "
                     + SERVICE_ID + " (" + e.getClass().getName() + ": "
-                    + e.getMessage() + ")");
+                    + e.getMessage() + ')');
             if (DEBUG) {
                 e.printStackTrace(System.err); //NOSONAR
             }

src/main/org/apache/tools/ant/DefaultLogger.java

@@ -215,7 +215,7 @@ public void targetStarted(BuildEvent event) {
         if (Project.MSG_INFO <= msgOutputLevel
             && !event.getTarget().getName().equals("")) {
             String msg = StringUtils.LINE_SEP
-                + event.getTarget().getName() + ":";
+                + event.getTarget().getName() + ':';
             printMessage(msg, out, event.getPriority());
             log(msg);
         }

src/main/org/apache/tools/ant/Location.java

@@ -140,7 +140,7 @@ public String toString() {
             buf.append(fileName);
 
             if (lineNumber != 0) {
-                buf.append(":");
+                buf.append(':');
                 buf.append(lineNumber);
             }
 

src/main/org/apache/tools/ant/NoBannerLogger.java

@@ -90,7 +90,7 @@ public void messageLogged(BuildEvent event) {
 
         synchronized (this) {
             if (null != targetName) {
-                out.println(StringUtils.LINE_SEP + targetName + ":");
+                out.println(StringUtils.LINE_SEP + targetName + ':');
                 targetName = null;
             }
         }

src/main/org/apache/tools/ant/PathTokenizer.java

@@ -118,7 +118,7 @@ public String nextToken() throws NoSuchElementException {
                     // we know we are on a DOS style platform and the next path
                     // starts with a slash or backslash, so we know this is a
                     // drive spec
-                    token += ":" + nextToken;
+                    token += ':' + nextToken;
                 } else {
                     // store the token just read for next time
                     lookahead = nextToken;
@@ -145,9 +145,9 @@ public String nextToken() throws NoSuchElementException {
                             // it indeed is a drive spec, get the next bit
                             String oneMore = tokenizer.nextToken().trim();
                             if (!oneMore.equals(File.pathSeparator)) {
-                                token += ":" + oneMore;
+                                token += ':' + oneMore;
                             } else {
-                                token += ":";
+                                token += ':';
                                 lookahead = oneMore;
                             }
                         }

src/main/org/apache/tools/ant/XmlLogger.java

@@ -136,7 +136,7 @@ private static class TimedElement {
 
         @Override
         public String toString() {
-            return element.getTagName() + ":" + element.getAttribute("name");
+            return element.getTagName() + ':' + element.getAttribute("name");
         }
     }
 

src/main/org/apache/tools/ant/input/DefaultInputHandler.java

@@ -105,10 +105,10 @@ protected String getPrompt(InputRequest request) {
                 }
                 first = false;
             }
-            sb.append(")");
+            sb.append(')');
             return sb.toString();
         } else if (def != null) {
-            return prompt + " [" + def + "]";
+            return prompt + " [" + def + ']';
         } else {
             return prompt;
         }

src/main/org/apache/tools/ant/taskdefs/Ant.java

@@ -449,7 +449,7 @@ && getOwningTarget() != null) {
                         .addLocationToBuildException(ex, getLocation());
                     throw be;
                 } finally {
-                    log("Exiting " + antFile + ".", Project.MSG_VERBOSE);
+                    log("Exiting " + antFile + '.', Project.MSG_VERBOSE);
                     newProject.fireSubBuildFinished(be);
                 }
             }

src/main/org/apache/tools/ant/taskdefs/Classloader.java

@@ -203,7 +203,7 @@ public void execute() {
                     // The core loader must be reverse
                     //reverse=true;
                 }
-                getProject().log("Setting parent loader " + name + " "
+                getProject().log("Setting parent loader " + name + ' '
                     + parent + " " + parentFirst, Project.MSG_DEBUG);
 
                 // The param is "parentFirst"
@@ -225,7 +225,7 @@ public void execute() {
                 for (int i = 0; i < list.length; i++) {
                     File f = new File(list[i]);
                     if (f.exists()) {
-                        log("Adding to class loader " + acl + " " + f.getAbsolutePath(),
+                        log("Adding to class loader " + acl + ' ' + f.getAbsolutePath(),
                                 Project.MSG_DEBUG);
                         acl.addPathElement(f.getAbsolutePath());
                     }