tier4: This test group includes every other test not covered by previous tiers. It includes, for example, vmTestbase suites for Hotspot, which run for many hours even on large machines. It also runs GUI tests, so the same TEST_JOBS and JTREG_KEYWORDS caveats apply.
JTReg tests can be selected either by picking a JTReg test group, or a selection of files or directories containing JTReg tests.
+JTReg tests can be selected either by picking a JTReg test group, or a selection of files or directories containing JTReg tests. Documentation can be found at https://openjdk.org/jtreg/, note especially the extensive FAQ.
JTReg test groups can be specified either without a test root, e.g. :tier1 (or tier1, the initial colon is optional), or with, e.g. hotspot:tier1, test/jdk:jdk_util or $(TOPDIR)/test/hotspot/jtreg:hotspot_all. The test root can be specified either as an absolute path, or a path relative to the JDK top directory, or the test directory. For simplicity, the hotspot JTReg test root, which really is hotspot/jtreg can be abbreviated as just hotspot.
When specified without a test root, all matching groups from all test roots will be added. Otherwise, only the group from the specified test root will be added.
Individual JTReg tests or directories containing JTReg tests can also be specified, like test/hotspot/jtreg/native_sanity/JniVersion.java or hotspot/jtreg/native_sanity. Just like for test root selection, you can either specify an absolute path (which can even point to JTReg tests outside the source tree), or a path relative to either the JDK top directory or the test directory. hotspot can be used as an alias for hotspot/jtreg here as well.