src/java.base/share/classes/java/lang/Thread.java

@@ -143,11 +143,11 @@
     private static native void registerNatives();
     static {
         registerNatives();
     }
 
-    private volatile char  name[];
+    private volatile String name;
     private int            priority;
     private Thread         threadQ;
     private long           eetop;
 
     /* Whether or not to single_step this thread. */

@@ -364,11 +364,11 @@
                       long stackSize, AccessControlContext acc) {
         if (name == null) {
             throw new NullPointerException("name cannot be null");
         }
 
-        this.name = name.toCharArray();
+        this.name = name;
 
         Thread parent = currentThread();
         SecurityManager security = System.getSecurityManager();
         if (g == null) {
             /* Determine if it's an applet or not */

@@ -1117,11 +1117,15 @@
      * @see        #getName
      * @see        #checkAccess()
      */
     public final synchronized void setName(String name) {
         checkAccess();
-        this.name = name.toCharArray();
+        if (name == null) {
+            throw new NullPointerException("name cannot be null");
+        }
+
+        this.name = name;
         if (threadStatus != 0) {
             setNativeName(name);
         }
     }
 

@@ -1130,11 +1134,11 @@
      *
      * @return  this thread's name.
      * @see     #setName(String)
      */
     public final String getName() {
-        return new String(name, true);
+        return name;
     }
 
     /**
      * Returns the thread group to which this thread belongs.
      * This method returns null if this thread has died