Hi,
Out of all the methods on Unsafe i think the
monitorEnter/monitorExit/tryMonitorEnter are the least used and are very strong
candidates for removal.
99% of use-cases are supported by classes in the java.util.concurrent.locks
package.
Within the JDK itself it is only used in one JDK test file
test/java/lang/ProcessBuilder/Basic.java:
while (unsafe.tryMonitorEnter(s)) {
unsafe.monitorExit(s);
Thread.sleep(1);
}
for a test verifying an EOF is received on pending reads and it is polling to
check when the process builder acquires the lock before destroying the process,
presumably to avoid some sort of race condition that occasionally causes the
test to fail.
I believe this test as been through a number of rounds, i stared at things for
a bit, but cannot quickly work out a replacement; i lack the knowledge on this
area.
Outside of the JDK i can only find one usage of monitorExit/Enter (according to
grep code) in JBoss modules, and i believe this is only used on Java 1.6 to
work around some limitations in class loading that were fixed in 1.7.
Given such very limited use i propose to remove these methods after having
worked out a fix for ProcessBuilder/Basic.java test.
Paul.
