HADOOP-15549 modified loadFirst function in MetricsConfig, and forget to set the DelimiterHandler, which caused that when loading the properties file, if the configured value is a String List, the value will not be loaded as a String Array, but just a String. For example, if we set
in hadoop-metrics2.properties. If we use conf.getStringArray("*.sink.ganglia.dmax") to get the value list, we will get an array with single element, the content of which is "jvm.metrics.threadsBlocked=70,jvm.metrics.memHeapUsedM=40", which wil cause an error during loadGangliaConf. loadGangliaConf will assume that the value of jvm.metrics.threadsBlocked is "70, jvm.metrics.memHeapUsedM", which will cause an error "java.lang.NumberFormatException: For input string: "70,jvm.metrics.memHeapUsedM".