Fwd: RFR(s): 8153330: deprecate Runtime.traceInstructions & traceMethodCalls for removal

[Stuart Marks]

I just posted this to core-libs-dev, and I figured I should run this by 
Hotspot-land. There isn't any double-secret-intrinsic magic that Hotspot does 
with these methods, is there? Anybody see any issue with deprecating and 
eventually removing these methods?

They won't be removed immediately, but the proposal is to deprecate them in JDK 
9, marked for removal in a future release.

Thanks,

s'marks


-------- Forwarded Message --------
Subject: RFR(s): 8153330: deprecate Runtime.traceInstructions & traceMethodCalls 
for removal
Date: Tue, 19 Apr 2016 15:11:38 -0700
From: Stuart Marks <stuart.marks at oracle.com>
To: core-libs-dev <core-libs-dev at openjdk.java.net>

Hi all,

I missed a couple bits of cruft in the previous round of java.lang deprecations:
the Runtime.traceInstructions() and traceMethodCalls() methods.

Their implementations are empty. That is, they do absolutely nothing.

They're only mentioned a couple times in the JDK, in CORBA (!) and in some RMI
tests (!), and in a few symbol files. On grepcode.com, there are a couple uses,
mainly attempting to enable these in response to some debugging flag being given.

Thus, I propose these be deprecated for removal. Please review diff below.

Thanks,

s'marks



diff -r 92280897299f src/java.base/share/classes/java/lang/Runtime.java
--- a/src/java.base/share/classes/java/lang/Runtime.java	Mon Apr 18 14:10:14
2016 -0700
+++ b/src/java.base/share/classes/java/lang/Runtime.java	Tue Apr 19 15:04:25
2016 -0700
@@ -718,41 +718,27 @@
      }

      /**
-     * Enables/Disables tracing of instructions.
-     * If the {@code boolean} argument is {@code true}, this
-     * method suggests that the Java virtual machine emit debugging
-     * information for each instruction in the virtual machine as it
-     * is executed. The format of this information, and the file or other
-     * output stream to which it is emitted, depends on the host environment.
-     * The virtual machine may ignore this request if it does not support
-     * this feature. The destination of the trace output is system
-     * dependent.
-     * <p>
-     * If the {@code boolean} argument is {@code false}, this
-     * method causes the virtual machine to stop performing the
-     * detailed instruction trace it is performing.
-     *
-     * @param   on   {@code true} to enable instruction tracing;
-     *               {@code false} to disable this feature.
+     * Not implemented.
+     *
+     * @deprecated
+     * This method was intended to control instruction tracing.
+     * It has been superseded by JVM-specific tracing mechanisms.
+     *
+     * @param on ignored
       */
+    @Deprecated(since="9", forRemoval=true)
      public void traceInstructions(boolean on) { }

      /**
-     * Enables/Disables tracing of method calls.
-     * If the {@code boolean} argument is {@code true}, this
-     * method suggests that the Java virtual machine emit debugging
-     * information for each method in the virtual machine as it is
-     * called. The format of this information, and the file or other output
-     * stream to which it is emitted, depends on the host environment. The
-     * virtual machine may ignore this request if it does not support
-     * this feature.
-     * <p>
-     * Calling this method with argument false suggests that the
-     * virtual machine cease emitting per-call debugging information.
-     *
-     * @param   on   {@code true} to enable instruction tracing;
-     *               {@code false} to disable this feature.
+     * Not implemented.
+     *
+     * @deprecated
+     * This method was intended to control method call tracing.
+     * It has been superseded by JVM-specific tracing mechanisms.
+     *
+     * @param on ignored
       */
+    @Deprecated(since="9", forRemoval=true)
      public void traceMethodCalls(boolean on) { }

      /**