8351821: VMManagementImpl.c avoid switching off warnings

Reviewed-by: ihse, kevinw

Author: MBaesken

make/modules/java.management/Lib.gmk

@@ -34,8 +34,6 @@ include LibCommon.gmk
 $(eval $(call SetupJdkLibrary, BUILD_LIBMANAGEMENT, \
     NAME := management, \
     OPTIMIZATION := HIGH, \
-    DISABLED_WARNINGS_gcc_VMManagementImpl.c := unused-variable, \
-    DISABLED_WARNINGS_clang_VMManagementImpl.c := unused-variable, \
     JDK_LIBS := java.base:libjava java.base:libjvm, \
     LIBS_aix := -lperfstat, \
     LIBS_windows := advapi32.lib psapi.lib, \

src/java.management/share/native/libmanagement/VMManagementImpl.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2016, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2025, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -37,13 +37,9 @@ Java_sun_management_VMManagementImpl_getVersion0
 {
     char buf[MAX_VERSION_LEN];
     jstring version_string = NULL;
-
     unsigned int major = ((unsigned int) jmm_version & 0x0FFF0000) >> 16;
     unsigned int minor = ((unsigned int) jmm_version & 0xFF00) >> 8;
 
-    // for internal use
-    unsigned int micro = (unsigned int) jmm_version & 0xFF;
-
     snprintf(buf, sizeof(buf), "%d.%d", major, minor);
     version_string = (*env)->NewStringUTF(env, buf);
     return version_string;
@@ -64,7 +60,7 @@ Java_sun_management_VMManagementImpl_initOptionalSupportFields
   (JNIEnv *env, jclass cls)
 {
     jmmOptionalSupport mos;
-    jint ret = jmm_interface->GetOptionalSupport(env, &mos);
+    jmm_interface->GetOptionalSupport(env, &mos);
 
     jboolean value;