Changing the nextArg value of MethodHandlesTest to be bigger than Integer.MAX_VALUE to actually test long arguments reveals a bug on x86_64:

$ /java/re/jdk/7/promoted/latest/binaries/solaris-x64/bin/amd64/java -showversion -Xint -XX:+UnlockExperimentalVMOptions -XX:+EnableMethodHandles -classpath /java/devtools/share/junit/latest/junit.jar:. org.junit.runner.JUnitCore MethodHandlesTest
java version "1.7.0-ea"
Java(TM) SE Runtime Environment (build 1.7.0-ea-b85)
Java HotSpot(TM) 64-Bit Server VM (build 17.0-b10, interpreted mode)

JUnit version 4.4
Java HotSpot(TM) 64-Bit Server VM warning: JSR 292 invokedynamic is disabled in this JVM. Use -XX:+UnlockExperimentalVMOptions -XX:+EnableInvokeDynamic to enable.
.IIIIII.assertCalled s3:
expected: [s3, [1000000000003]]
actual: [s3, [-2749506449405]]
ex. types: [s3, [Long]]
act. types: [s3, [Long]]
E....I......Segmentation Fault