Summary

Deprecate the IgnoreUnverifiableClassesDuringDump diagnostic vm option in JDK10.

Change the default boolean value of the IgnoreUnverifiableClassesDuringDump vm option from 'false' to 'true'.

Problem

Existing big applications, such as the WLS (WebLogic Server), comprises of jar files which contains legacy classes with classfile version < JDK 1.5. Those classes cannot be verified during CDS dumping. Currently, CDS dumping will exit if there exists any classes which cannot be verified. Some of those classes may exist in only binary form and recompiling them with a newer version of JDK may not be possible. In the ease of use point of view, the CDS dumping should not exit when it encounters unverifiable classes but should ignore those classes and not including those classes in the shared archive.

Solution

Currently, there's a way to ignore unverifiable classes during CDS dumping by using the following vm options:

-XX:+UnlockDiagnosticVMOptions, -XX:+IgnoreUnverifiableClassesDuringDump

Note that the UnlockDiagnosticVMOptions is required because the IgnoreUnverifiableClassesDuringDump is a diagnostic vm option.

The proposed solution is to enable the IgnoreUnverifiableClassesDuringDump option by default.

Specification

diff --git a/src/share/vm/runtime/globals.hpp b/src/share/vm/runtime/globals.hpp
--- a/src/share/vm/runtime/globals.hpp
+++ b/src/share/vm/runtime/globals.hpp
@@ -3934,7 +3934,7 @@
           "Average number of symbols per bucket in shared table")           \
           range(2, 246)                                                     \
                                                                             \
-  diagnostic(bool, IgnoreUnverifiableClassesDuringDump, false,              \
+  diagnostic(bool, IgnoreUnverifiableClassesDuringDump, true,              \
           "Do not quit -Xshare:dump even if we encounter unverifiable "     \
           "classes. Just exclude them from the shared dictionary.")         \
                                                                             \

diff --git a/src/share/vm/runtime/arguments.cpp b/src/share/vm/runtime/arguments.cpp
--- a/src/share/vm/runtime/arguments.cpp
+++ b/src/share/vm/runtime/arguments.cpp
@@ -381,6 +381,7 @@
   { "MaxRAMFraction",               JDK_Version::jdk(10),  JDK_Version::undefined(), JDK_Version::undefined() },
   { "MinRAMFraction",               JDK_Version::jdk(10),  JDK_Version::undefined(), JDK_Version::undefined() },
   { "InitialRAMFraction",           JDK_Version::jdk(10),  JDK_Version::undefined(), JDK_Version::undefined() },
+  { "IgnoreUnverifiableClassesDuringDump", JDK_Version::jdk(10),  JDK_Version::undefined(), JDK_Version::undefined() },