If you see this in your logs:

Caused by: java.lang.NoSuchMethodError: java.util.concurrent.ConcurrentHashMap.keySet()Ljava/util/concurrent/ConcurrentHashMap$KeySetView;
  at org.apache.hadoop.hbase.master.ServerManager.findServerWithSameHostnamePortWithLock(ServerManager.java:393)
  at org.apache.hadoop.hbase.master.ServerManager.checkAndRecordNewServer(ServerManager.java:307)
  at org.apache.hadoop.hbase.master.ServerManager.regionServerStartup(ServerManager.java:244)
  at org.apache.hadoop.hbase.master.MasterRpcServices.regionServerStartup(MasterRpcServices.java:304)
  at org.apache.hadoop.hbase.protobuf.generated.RegionServerStatusProtos$RegionServerStatusService$2.callBlockingMethod(RegionServerStatusProtos.java:7910)
  at org.apache.hadoop.hbase.ipc.RpcServer.call(RpcServer.java:2020)
  ... 4 more

then check if you compiled with jdk8 and tried to run it on jdk7. If so, this won't work. Run on jdk8 or recompile with jdk7. See HBASE-10607 [JDK8] NoSuchMethodError involving ConcurrentHashMap.keySet if running on JRE 7.