Replace StringBuffer with StringBuilder, other minor String optimizations

src/main/javassist/ClassPoolTail.java

@@ -54,7 +54,7 @@ public InputStream openClassfile(String classname) {
             char sep = File.separatorChar;
             String filename = directory + sep
                 + classname.replace('.', sep) + ".class";
-            return new FileInputStream(filename.toString());
+            return new FileInputStream(filename);
         }
         catch (FileNotFoundException e) {}
         catch (SecurityException e) {}
@@ -187,7 +187,7 @@ public URL find(String classname) {
 
     @Override
     public String toString() {
-        return jarfileURL == null ? "<null>" : jarfileURL.toString();
+        return jarfileURL == null ? "<null>" : jarfileURL;
     }
 }
 
@@ -200,7 +200,7 @@ public ClassPoolTail() {
 
     @Override
     public String toString() {
-        StringBuffer buf = new StringBuffer();
+        StringBuilder buf = new StringBuilder();
         buf.append("[class path: ");
         ClassPathList list = pathList;
         while (list != null) {

src/main/javassist/CtBehavior.java

@@ -100,7 +100,7 @@ void copy(CtBehavior src, boolean isCons, ClassMap map)
     }
 
     @Override
-    protected void extendToString(StringBuffer buffer) {
+    protected void extendToString(StringBuilder buffer) {
         buffer.append(' ');
         buffer.append(getName());
         buffer.append(' ');

src/main/javassist/CtClass.java

@@ -200,20 +200,20 @@ protected CtClass(String name) {
      */
     @Override
     public String toString() {
-        StringBuffer buf = new StringBuffer(getClass().getName());
-        buf.append("@");
+        StringBuilder buf = new StringBuilder(getClass().getName());
+        buf.append('@');
         buf.append(Integer.toHexString(hashCode()));
-        buf.append("[");
+        buf.append('[');
         extendToString(buf);
-        buf.append("]");
+        buf.append(']');
         return buf.toString();
     }
 
     /**
      * Implemented in subclasses to add to the {@link #toString()} result.
      * Subclasses should put a space before each token added to the buffer.
      */
-    protected void extendToString(StringBuffer buffer) {
+    protected void extendToString(StringBuilder buffer) {
         buffer.append(getName());
     }
 

src/main/javassist/CtClassType.java

@@ -106,7 +106,7 @@ class CtClassType extends CtClass {
     }
 
     @Override
-    protected void extendToString(StringBuffer buffer) {
+    protected void extendToString(StringBuilder buffer) {
         if (wasChanged)
             buffer.append("changed ");
 
@@ -125,7 +125,7 @@ protected void extendToString(StringBuffer buffer) {
             if (ext != null) {
                 String name = ext.getName();
                 if (!name.equals("java.lang.Object"))
-                    buffer.append(" extends " + ext.getName());
+                    buffer.append(" extends ").append(ext.getName());
             }
         }
         catch (NotFoundException e) {
@@ -155,7 +155,7 @@ protected void extendToString(StringBuffer buffer) {
                    memCache.methodHead(), memCache.lastMethod());
     }
 
-    private void exToString(StringBuffer buffer, String msg,
+    private void exToString(StringBuilder buffer, String msg,
                             CtMember head, CtMember tail) {
         buffer.append(msg);
         while (head != tail) {

src/main/javassist/CtField.java

@@ -128,7 +128,7 @@ public String toString() {
     }
 
     @Override
-    protected void extendToString(StringBuffer buffer) {
+    protected void extendToString(StringBuilder buffer) {
         buffer.append(' ');
         buffer.append(getName());
         buffer.append(' ');

src/main/javassist/CtMember.java

@@ -30,7 +30,7 @@ public abstract class CtMember {
      */
     static class Cache extends CtMember {
         @Override
-        protected void extendToString(StringBuffer buffer) {}
+        protected void extendToString(StringBuilder buffer) {}
         @Override
         public boolean hasAnnotation(String clz) { return false; }
         @Override
@@ -155,13 +155,13 @@ void nameReplaced() {}
 
     @Override
     public String toString() {
-        StringBuffer buffer = new StringBuffer(getClass().getName());
-        buffer.append("@");
+        StringBuilder buffer = new StringBuilder(getClass().getName());
+        buffer.append('@');
         buffer.append(Integer.toHexString(hashCode()));
-        buffer.append("[");
+        buffer.append('[');
         buffer.append(Modifier.toString(getModifiers()));
         extendToString(buffer);
-        buffer.append("]");
+        buffer.append(']');
         return buffer.toString();
     }
 
@@ -172,7 +172,7 @@ public String toString() {
      * provided first; subclasses should provide additional data such
      * as return type, field or method name, etc.
      */
-    protected abstract void extendToString(StringBuffer buffer);
+    protected abstract void extendToString(StringBuilder buffer);
 
     /**
      * Returns the class that declares this member.

src/main/javassist/CtNewClass.java

@@ -45,7 +45,7 @@ class CtNewClass extends CtClassType {
     }
 
     @Override
-    protected void extendToString(StringBuffer buffer) {
+    protected void extendToString(StringBuilder buffer) {
         if (hasConstructor)
             buffer.append("hasConstructor ");
 

src/main/javassist/bytecode/Descriptor.java

@@ -109,7 +109,7 @@ else if (c == 'Z')
 
         if (arrayDim == 0)
             return name;
-        StringBuffer sbuf = new StringBuffer(name);
+        StringBuilder sbuf = new StringBuilder(name);
         do {
             sbuf.append("[]");
         } while (--arrayDim > 0);
@@ -157,7 +157,7 @@ public static String rename(String desc, String oldname, String newname) {
         if (desc.indexOf(oldname) < 0)
             return desc;
 
-        StringBuffer newdesc = new StringBuffer();
+        StringBuilder newdesc = new StringBuilder();
         int head = 0;
         int i = 0;
         for (;;) {
@@ -200,7 +200,7 @@ public static String rename(String desc, Map<String,String> map) {
         if (map == null)
             return desc;
 
-        StringBuffer newdesc = new StringBuffer();
+        StringBuilder newdesc = new StringBuilder();
         int head = 0;
         int i = 0;
         for (;;) {
@@ -237,12 +237,12 @@ public static String rename(String desc, Map<String,String> map) {
      * Returns the descriptor representing the given type.
      */
     public static String of(CtClass type) {
-        StringBuffer sbuf = new StringBuffer();
+        StringBuilder sbuf = new StringBuilder();
         toDescriptor(sbuf, type);
         return sbuf.toString();
     }
 
-    private static void toDescriptor(StringBuffer desc, CtClass type) {
+    private static void toDescriptor(StringBuilder desc, CtClass type) {
         if (type.isArray()) {
             desc.append('[');
             try {
@@ -284,7 +284,7 @@ public static String ofConstructor(CtClass[] paramTypes) {
      * @param paramTypes parameter types
      */
     public static String ofMethod(CtClass returnType, CtClass[] paramTypes) {
-        StringBuffer desc = new StringBuffer();
+        StringBuilder desc = new StringBuilder();
         desc.append('(');
         if (paramTypes != null) {
             int n = paramTypes.length;
@@ -323,7 +323,7 @@ public static String appendParameter(String classname, String desc) {
         int i = desc.indexOf(')');
         if (i < 0)
             return desc;
-        StringBuffer newdesc = new StringBuffer();
+        StringBuilder newdesc = new StringBuilder();
         newdesc.append(desc.substring(0, i));
         newdesc.append('L');
         newdesc.append(classname.replace('.', '/'));
@@ -361,7 +361,7 @@ public static String appendParameter(CtClass type, String descriptor) {
         int i = descriptor.indexOf(')');
         if (i < 0)
             return descriptor;
-        StringBuffer newdesc = new StringBuffer();
+        StringBuilder newdesc = new StringBuilder();
         newdesc.append(descriptor.substring(0, i));
         toDescriptor(newdesc, type);
         newdesc.append(descriptor.substring(i));
@@ -395,7 +395,7 @@ public static String changeReturnType(String classname, String desc) {
         int i = desc.indexOf(')');
         if (i < 0)
             return desc;
-        StringBuffer newdesc = new StringBuffer();
+        StringBuilder newdesc = new StringBuilder();
         newdesc.append(desc.substring(0, i + 1));
         newdesc.append('L');
         newdesc.append(classname.replace('.', '/'));
@@ -561,7 +561,7 @@ private static int toCtClass(ClassPool cp, String desc, int i,
         }
 
         if (arrayDim > 0) {
-            StringBuffer sbuf = new StringBuffer(name);
+            StringBuilder sbuf = new StringBuilder(name);
             while (arrayDim-- > 0)
                 sbuf.append("[]");
 
@@ -719,7 +719,7 @@ public static String toString(String desc) {
 
     static class PrettyPrinter {
         static String toString(String desc) {
-            StringBuffer sbuf = new StringBuffer();
+            StringBuilder sbuf = new StringBuilder();
             if (desc.charAt(0) == '(') {
                 int pos = 1;
                 sbuf.append('(');
@@ -738,7 +738,7 @@ static String toString(String desc) {
             return sbuf.toString();
         }
 
-        static int readType(StringBuffer sbuf, int pos, String desc) {
+        static int readType(StringBuilder sbuf, int pos, String desc) {
             char c = desc.charAt(pos);
             int arrayDim = 0;
             while (c == '[') {

src/main/javassist/bytecode/InstructionPrinter.java

@@ -235,17 +235,17 @@ private static String fieldInfo(ConstPool pool, int index) {
 
 
     private static String lookupSwitch(CodeIterator iter, int pos) {
-        StringBuffer buffer = new StringBuffer("lookupswitch {\n");
+        StringBuilder buffer = new StringBuilder("lookupswitch {\n");
         int index = (pos & ~3) + 4;
         // default
-        buffer.append("\t\tdefault: ").append(pos + iter.s32bitAt(index)).append("\n");
+        buffer.append("\t\tdefault: ").append(pos + iter.s32bitAt(index)).append('\n');
         int npairs = iter.s32bitAt(index += 4);
         int end = npairs * 8 + (index += 4);
 
         for (; index < end; index += 8) {
             int match = iter.s32bitAt(index);
             int target = iter.s32bitAt(index + 4) + pos;
-            buffer.append("\t\t").append(match).append(": ").append(target).append("\n");
+            buffer.append("\t\t").append(match).append(": ").append(target).append('\n');
         }
 
         buffer.setCharAt(buffer.length() - 1, '}');
@@ -254,18 +254,18 @@ private static String lookupSwitch(CodeIterator iter, int pos) {
 
 
     private static String tableSwitch(CodeIterator iter, int pos) {
-        StringBuffer buffer = new StringBuffer("tableswitch {\n");
+        StringBuilder buffer = new StringBuilder("tableswitch {\n");
         int index = (pos & ~3) + 4;
         // default
-        buffer.append("\t\tdefault: ").append(pos + iter.s32bitAt(index)).append("\n");
+        buffer.append("\t\tdefault: ").append(pos + iter.s32bitAt(index)).append('\n');
         int low = iter.s32bitAt(index += 4);
         int high = iter.s32bitAt(index += 4);
         int end = (high - low + 1) * 4 + (index += 4);
 
         // Offset table
         for (int key = low; index < end; index += 4, key++) {
             int target = iter.s32bitAt(index) + pos;
-            buffer.append("\t\t").append(key).append(": ").append(target).append("\n");
+            buffer.append("\t\t").append(key).append(": ").append(target).append('\n');
         }
 
         buffer.setCharAt(buffer.length() - 1, '}');

src/main/javassist/bytecode/ParameterAnnotationsAttribute.java

@@ -201,7 +201,7 @@ public String toString() {
         StringBuilder sbuf = new StringBuilder();
         for (Annotation[] a : aa) {
             for (Annotation i : a)
-                sbuf.append(i.toString()).append(" ");
+                sbuf.append(i.toString()).append(' ');
 
             sbuf.append(", ");
         }