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

*** 1224,1234 ****
              throw new NullPointerException("name cannot be null");
          }
  
          this.name = name;
          if (threadStatus != 0) {
!             setNativeName(name);
          }
      }
  
      /**
       * Returns this thread's name.
--- 1224,1235 ----
              throw new NullPointerException("name cannot be null");
          }
  
          this.name = name;
          if (threadStatus != 0) {
!             // Don't modify JNI-attached threads
!             setNativeName(name, false);
          }
      }
  
      /**
       * Returns this thread's name.
*** 2140,2146 ****
      private native void setPriority0(int newPriority);
      private native void stop0(Object o);
      private native void suspend0();
      private native void resume0();
      private native void interrupt0();
!     private native void setNativeName(String name);
  }
--- 2141,2150 ----
      private native void setPriority0(int newPriority);
      private native void stop0(Object o);
      private native void suspend0();
      private native void resume0();
      private native void interrupt0();
! 
!     // May be called directly via JNI or reflection (when permitted) to
!     // allow JNI-attached threads to set their native name
!     private native void setNativeName(String name, boolean allowAttachedThread);
  }