Major Description
Since some JDBC Drivers have class initialization code to call `DriverManager`, we need to initialize DriverManager first in order to avoid potential deadlock situation like the following or STORM-2527.
Thread 9587: (state = BLOCKED) - sun.reflect.NativeConstructorAccessorImpl.newInstance0(java.lang.reflect.Constructor, java.lang.Object[]) @bci=0 (Compiled frame; information may be imprecise) - sun.reflect.NativeConstructorAccessorImpl.newInstance(java.lang.Object[]) @bci=85, line=62 (Compiled frame) - sun.reflect.DelegatingConstructorAccessorImpl.newInstance(java.lang.Object[]) @bci=5, line=45 (Compiled frame) - java.lang.reflect.Constructor.newInstance(java.lang.Object[]) @bci=79, line=423 (Compiled frame) - java.lang.Class.newInstance() @bci=138, line=442 (Compiled frame) - java.util.ServiceLoader$LazyIterator.nextService() @bci=119, line=380 (Interpreted frame) - java.util.ServiceLoader$LazyIterator.next() @bci=11, line=404 (Interpreted frame) - java.util.ServiceLoader$1.next() @bci=37, line=480 (Interpreted frame) - java.sql.DriverManager$2.run() @bci=21, line=603 (Interpreted frame) - java.sql.DriverManager$2.run() @bci=1, line=583 (Interpreted frame) - java.security.AccessController.doPrivileged(java.security.PrivilegedAction) @bci=0 (Compiled frame) - java.sql.DriverManager.loadInitialDrivers() @bci=27, line=583 (Interpreted frame) - java.sql.DriverManager.<clinit>() @bci=32, line=101 (Interpreted frame) - org.apache.phoenix.mapreduce.util.ConnectionUtil.getConnection(java.lang.String, java.lang.Integer, java.lang.String, java.util.Properties) @bci=12, line=98 (Interpreted frame) - org.apache.phoenix.mapreduce.util.ConnectionUtil.getInputConnection(org.apache.hadoop.conf.Configuration, java.util.Properties) @bci=22, line=57 (Interpreted frame) - org.apache.phoenix.mapreduce.PhoenixInputFormat.getQueryPlan(org.apache.hadoop.mapreduce.JobContext, org.apache.hadoop.conf.Configuration) @bci=61, line=116 (Interpreted frame) - org.apache.phoenix.mapreduce.PhoenixInputFormat.createRecordReader(org.apache.hadoop.mapreduce.InputSplit, org.apache.hadoop.mapreduce.TaskAttemptContext) @bci=10, line=71 (Interpreted frame) - org.apache.spark.rdd.NewHadoopRDD$$anon$1.<init>(org.apache.spark.rdd.NewHadoopRDD, org.apache.spark.Partition, org.apache.spark.TaskContext) @bci=233, line=156 (Interpreted frame) Thread 9170: (state = BLOCKED) - org.apache.phoenix.jdbc.PhoenixDriver.<clinit>() @bci=35, line=125 (Interpreted frame) - sun.reflect.NativeConstructorAccessorImpl.newInstance0(java.lang.reflect.Constructor, java.lang.Object[]) @bci=0 (Compiled frame) - sun.reflect.NativeConstructorAccessorImpl.newInstance(java.lang.Object[]) @bci=85, line=62 (Compiled frame) - sun.reflect.DelegatingConstructorAccessorImpl.newInstance(java.lang.Object[]) @bci=5, line=45 (Compiled frame) - java.lang.reflect.Constructor.newInstance(java.lang.Object[]) @bci=79, line=423 (Compiled frame) - java.lang.Class.newInstance() @bci=138, line=442 (Compiled frame) - org.apache.spark.sql.execution.datasources.jdbc.DriverRegistry$.register(java.lang.String) @bci=89, line=46 (Interpreted frame) - org.apache.spark.sql.execution.datasources.jdbc.JdbcUtils$$anonfun$createConnectionFactory$2.apply() @bci=7, line=53 (Interpreted frame) - org.apache.spark.sql.execution.datasources.jdbc.JdbcUtils$$anonfun$createConnectionFactory$2.apply() @bci=1, line=52 (Interpreted frame) - org.apache.spark.sql.execution.datasources.jdbc.JDBCRDD$$anon$1.<init>(org.apache.spark.sql.execution.datasources.jdbc.JDBCRDD, org.apache.spark.Partition, org.apache.spark.TaskContext) @bci=81, line=347 (Interpreted frame) - org.apache.spark.sql.execution.datasources.jdbc.JDBCRDD.compute(org.apache.spark.Partition, org.apache.spark.TaskContext) @bci=7, line=339 (Interpreted frame)
