The expressions module currently uses ASM 4 for generating class files. We should upgrade to ASM 5.0.4. In addition, with that version we can create Java 8 class files on trunk.
There is a clash with Apache TIKA, which uses the same old 4.x version. But ASM 5 is still compatible to ASM 4, if you pass the old ASM version to your own visitors. But on long term TIKA should upgrade, too, because currently it cannot parse Java 8 class files.
ASM 5.0 also fixes some bugs with Java 7 class files, so we should really upgrade.