src/share/classes/java/lang/reflect/Modifier.java

@@ -24,10 +24,11 @@
  */
 
 package java.lang.reflect;
 
 import java.security.AccessController;
+import java.util.StringJoiner;
 import sun.reflect.LangReflectAccess;
 import sun.reflect.ReflectionFactory;
 
 /**
  * The Modifier class provides {@code static} methods and

@@ -230,31 +231,28 @@
      * @param   mod a set of modifiers
      * @return  a string representation of the set of modifiers
      * represented by {@code mod}
      */
     public static String toString(int mod) {
-        StringBuilder sb = new StringBuilder();
-        int len;
+        StringJoiner sj = new StringJoiner(" ");
 
-        if ((mod & PUBLIC) != 0)        sb.append("public ");
-        if ((mod & PROTECTED) != 0)     sb.append("protected ");
-        if ((mod & PRIVATE) != 0)       sb.append("private ");
+        if ((mod & PUBLIC) != 0)        sj.add("public");
+        if ((mod & PROTECTED) != 0)     sj.add("protected");
+        if ((mod & PRIVATE) != 0)       sj.add("private");
 
         /* Canonical order */
-        if ((mod & ABSTRACT) != 0)      sb.append("abstract ");
-        if ((mod & STATIC) != 0)        sb.append("static ");
-        if ((mod & FINAL) != 0)         sb.append("final ");
-        if ((mod & TRANSIENT) != 0)     sb.append("transient ");
-        if ((mod & VOLATILE) != 0)      sb.append("volatile ");
-        if ((mod & SYNCHRONIZED) != 0)  sb.append("synchronized ");
-        if ((mod & NATIVE) != 0)        sb.append("native ");
-        if ((mod & STRICT) != 0)        sb.append("strictfp ");
-        if ((mod & INTERFACE) != 0)     sb.append("interface ");
-
-        if ((len = sb.length()) > 0)    /* trim trailing space */
-            return sb.toString().substring(0, len-1);
-        return "";
+        if ((mod & ABSTRACT) != 0)      sj.add("abstract");
+        if ((mod & STATIC) != 0)        sj.add("static");
+        if ((mod & FINAL) != 0)         sj.add("final");
+        if ((mod & TRANSIENT) != 0)     sj.add("transient");
+        if ((mod & VOLATILE) != 0)      sj.add("volatile");
+        if ((mod & SYNCHRONIZED) != 0)  sj.add("synchronized");
+        if ((mod & NATIVE) != 0)        sj.add("native");
+        if ((mod & STRICT) != 0)        sj.add("strictfp");
+        if ((mod & INTERFACE) != 0)     sj.add("interface");
+
+        return sj.toString();
     }
 
     /*
      * Access modifier flag constants from tables 4.1, 4.4, 4.5, and 4.7 of
      * <cite>The Java&trade; Virtual Machine Specification</cite>