[KYLIN-2464] Use ConcurrentMap instead of ConcurrentHashMap to avoid runtime errors

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: v2.0.0
• Assignee: Unassigned
• Reporter: Wang Cheng
• Created: 24/Feb/17 02:12
• Updated: 30/Apr/17 12:21
• Resolved: 24/Feb/17 10:47

Description

There are some runtime errors happened when code is compiled with high Java version and runs on low Java version, for example:

Exception in thread "main" java.lang.NoSuchMethodError: java.util.concurrent.ConcurrentHashMap.keySet()Ljava/util/concurrent/ConcurrentHashMap$KeySetView;
at org.apache.kylin.cube.CubeManager.getInstance(SourceFile:110)
at org.apache.kylin.tool.CubeMigrationCheckCLI.checkCube(CubeMigrationCheckCLI.java:141)
at org.apache.kylin.tool.CubeMigrationCheckCLI.execute(CubeMigrationCheckCLI.java:121)
at org.apache.kylin.tool.CubeMigrationCLI.checkMigrationSuccess(CubeMigrationCLI.java:170)
at org.apache.kylin.tool.CubeMigrationCLI.moveCube(CubeMigrationCLI.java:156)
at org.apache.kylin.tool.CubeMigrationCLI.moveCube(CubeMigrationCLI.java:165)
at io.kyligence.kap.tool.release.KapReleaseCLI.main(KapReleaseCLI.java:66)

It's a better idea that declaring a variable to be an interface.