Initially reported here:
 https://www.reddit.com/r/java/comments/8i9nd6/a_surprising_feature_of_method_references/

See the minimal test here:
  http://cr.openjdk.java.net/~shade/8202922/webrev.01/

It fails with:

$ CONF=linux-x86_64-normal-server-fastdebug make images run-test TEST=jdk/java/lang/invoke/lambda/LambdaSerializationIdentity.java
...
STDERR:
java.lang.IllegalStateException: Identity is broken after serialization:
input1 = LambdaSerializationIdentity$$Lambda$45/0x00000001000ca440@391d7b1e
input2 = LambdaSerializationIdentity$$Lambda$46/0x00000001000c9840@76da0005
output1 = LambdaSerializationIdentity$$Lambda$47/0x00000001000c9040@1513b46e
output2 = LambdaSerializationIdentity$$Lambda$47/0x00000001000c9040@1513b46e

This comes from two static method references, which are not equal to each other before serialization, but are equal after the serialization. So, two distinct Objects instantiated with method references evaluation come into serialization, and two identical Objects come out.