--- a/src/hotspot/share/classfile/javaClasses.cpp	Wed Apr 17 09:25:27 2019 +0200
+++ b/src/hotspot/share/classfile/javaClasses.cpp	Wed Apr 17 09:29:25 2019 +0200
@@ -1714,20 +1714,13 @@
 
 
 jlong java_lang_Thread::stackSize(oop java_thread) {
-  if (_stackSize_offset > 0) {
-    return java_thread->long_field(_stackSize_offset);
-  } else {
-    return 0;
-  }
+  return java_thread->long_field(_stackSize_offset);
 }
 
 // Write the thread status value to threadStatus field in java.lang.Thread java class.
 void java_lang_Thread::set_thread_status(oop java_thread,
                                          java_lang_Thread::ThreadStatus status) {
-  // The threadStatus is only present starting in 1.5
-  if (_thread_status_offset > 0) {
-    java_thread->int_field_put(_thread_status_offset, status);
-  }
+  java_thread->int_field_put(_thread_status_offset, status);
 }
 
 // Read thread status value from threadStatus field in java.lang.Thread java class.
@@ -1737,62 +1730,31 @@
   assert(Threads_lock->owned_by_self() || Thread::current()->is_VM_thread() ||
          JavaThread::current()->thread_state() == _thread_in_vm,
          "Java Thread is not running in vm");
-  // The threadStatus is only present starting in 1.5
-  if (_thread_status_offset > 0) {
-    return (java_lang_Thread::ThreadStatus)java_thread->int_field(_thread_status_offset);
-  } else {
-    // All we can easily figure out is if it is alive, but that is
-    // enough info for a valid unknown status.
-    // These aren't restricted to valid set ThreadStatus values, so
-    // use JVMTI values and cast.
-    JavaThread* thr = java_lang_Thread::thread(java_thread);
-    if (thr == NULL) {
-      // the thread hasn't run yet or is in the process of exiting
-      return NEW;
-    }
-    return (java_lang_Thread::ThreadStatus)JVMTI_THREAD_STATE_ALIVE;
-  }
+  return (java_lang_Thread::ThreadStatus)java_thread->int_field(_thread_status_offset);
 }
 
 
 jlong java_lang_Thread::thread_id(oop java_thread) {
-  // The thread ID field is only present starting in 1.5
-  if (_tid_offset > 0) {
-    return java_thread->long_field(_tid_offset);
-  } else {
-    return 0;
-  }
+  return java_thread->long_field(_tid_offset);
 }
 
 oop java_lang_Thread::park_blocker(oop java_thread) {
-  assert(JDK_Version::current().supports_thread_park_blocker() &&
-         _park_blocker_offset != 0, "Must support parkBlocker field");
-
-  if (_park_blocker_offset > 0) {
-    return java_thread->obj_field(_park_blocker_offset);
-  }
-
-  return NULL;
+  assert(JDK_Version::current().supports_thread_park_blocker(),
+         "Must support parkBlocker field");
+
+  return java_thread->obj_field(_park_blocker_offset);
 }
 
 jlong java_lang_Thread::park_event(oop java_thread) {
-  if (_park_event_offset > 0) {
-    return java_thread->long_field(_park_event_offset);
-  }
-  return 0;
+  return java_thread->long_field(_park_event_offset);
 }
 
 bool java_lang_Thread::set_park_event(oop java_thread, jlong ptr) {
-  if (_park_event_offset > 0) {
-    java_thread->long_field_put(_park_event_offset, ptr);
-    return true;
-  }
-  return false;
-}
-
+  java_thread->long_field_put(_park_event_offset, ptr);
+  return true;
+}
 
 const char* java_lang_Thread::thread_status_name(oop java_thread) {
-  assert(_thread_status_offset != 0, "Must have thread status");
   ThreadStatus status = (java_lang_Thread::ThreadStatus)java_thread->int_field(_thread_status_offset);
   switch (status) {
     case NEW                      : return "NEW";