--- old/src/os/windows/vm/os_windows.cpp	2015-06-15 21:33:25.036147070 +0200
+++ new/src/os/windows/vm/os_windows.cpp	2015-06-15 21:33:24.872141561 +0200
@@ -1899,7 +1899,7 @@
 Semaphore::Semaphore(uint value, uint max) {
   _semaphore = ::CreateSemaphore(NULL, value, max, NULL);
 
-  guarantee(_semaphore != NULL, err_msg("CreateSemaphore failed: %ld", GetLastError()));
+  assert(_semaphore != NULL, err_msg("CreateSemaphore failed: %ld", GetLastError()));
 }
 
 Semaphore::~Semaphore() {
@@ -1911,7 +1911,7 @@
 void Semaphore::signal(uint count) {
   BOOL ret = ::ReleaseSemaphore(_semaphore, count, NULL);
 
-  guarantee(ret != 0, err_msg("ReleaseSemaphore failed: %d", GetLastError()));
+  assert(ret != 0, err_msg("ReleaseSemaphore failed: %d", GetLastError()));
 }
 
 void Semaphore::signal() {
@@ -1920,17 +1920,7 @@
 
 void Semaphore::wait() {
   DWORD ret = ::WaitForSingleObject(_semaphore, INFINITE);
-  guarantee(ret == WAIT_OBJECT_0, err_msg("WaitForSingleObject failed: %d", GetLastError()));
-}
-
-bool Semaphore::trywait() {
-  Unimplemented();
-  return false;
-}
-
-bool Semaphore::timedwait(unsigned int sec, int nsec) {
-  Unimplemented();
-  return false;
+  assert(ret == WAIT_OBJECT_0, err_msg("WaitForSingleObject failed: %d", GetLastError()));
 }
 
 // sun.misc.Signal