Could not find or load main class org.apache.hadoop.mapreduce.v2.app.MRAppMaster

I had the same problem and resolved by adding this in mapred-site.xml (so edit your mapreduce.application.classpath property)

<property>     <name>mapreduce.application.classpath</name>    <value>$HADOOP_MAPRED_HOME/share/hadoop/mapreduce/*,$HADOOP_MAPRED_HOME/share/hadoop/mapreduce/lib/*,$HADOOP_MAPRED_HOME/share/hadoop/common/*,$HADOOP_MAPRED_HOME/share/hadoop/common/lib/*,$HADOOP_MAPRED_HOME/share/hadoop/yarn/*,$HADOOP_MAPRED_HOME/share/hadoop/yarn/lib/*,$HADOOP_MAPRED_HOME/share/hadoop/hdfs/*,$HADOOP_MAPRED_HOME/share/hadoop/hdfs/lib/*</value></property>

Just edit the mapred-site.xml file :

Add following properties:

1. <property> <name>mapreduce.framework.name</name> <value>yarn</value></property>

2. <property> <name>yarn.app.mapreduce.am.env</name> <value>HADOOP_MAPRED_HOME=/Users/adityaatri/Applications/hadoop-3.1.3</value></property>

3. <property> <name>mapreduce.map.env</name> <value>HADOOP_MAPRED_HOME=/Users/adityaatri/Applications/hadoop-3.1.3</value></property>

4. <property> <name>mapreduce.reduce.env</name> <value>HADOOP_MAPRED_HOME=/Users/adityaatri/Applications/hadoop-3.1.3</value></property>

Now for all the above 4 properties, replace the path /Users/adityaatri/Applications/hadoop-3.1.3 with your Hadoop Home Address.

Now add the 5th property :

5. <property> <name>mapreduce.application.classpath</name> <value></value></property>

The <value> element must be filled with content after executing below commands in your terminal :

1. export HADOOP_CLASSPATH=$(hadoop classpath)

2. echo $HADOOP_CLASSPATH

The output from my terminal :

/Users/adityaatri/Applications/hadoop-3.1.3/etc/hadoop:/Users/adityaatri/Applications/hadoop-3.1.3/share/hadoop/common/lib/*:/Users/adityaatri/Applications/hadoop-3.1.3/share/hadoop/common/*:/Users/adityaatri/Applications/hadoop-3.1.3/share/hadoop/hdfs:/Users/adityaatri/Applications/hadoop-3.1.3/share/hadoop/hdfs/lib/*:/Users/adityaatri/Applications/hadoop-3.1.3/share/hadoop/hdfs/*:/Users/adityaatri/Applications/hadoop-3.1.3/share/hadoop/mapreduce/lib/*:/Users/adityaatri/Applications/hadoop-3.1.3/share/hadoop/mapreduce/*:/Users/adityaatri/Applications/hadoop-3.1.3/share/hadoop/yarn:/Users/adityaatri/Applications/hadoop-3.1.3/share/hadoop/yarn/lib/*:/Users/adityaatri/Applications/hadoop-3.1.3/share/hadoop/yarn/*

Copy this content inside the <value> element of the 5th property.

Now you will not get any error. :)

I added following property in yarn-site.xml

<property>  <name>yarn.application.classpath</name>  <value> $HADOOP_CONF_DIR,$HADOOP_COMMON_HOME/share/hadoop/common/*,$HADOOP_COMMON_HOME/share/hadoop/common/lib/*,$HADOOP_HDFS_HOME/share/hadoop/hdfs/*,$HADOOP_HDFS_HOME/share/hadoop/hdfs/lib/*,$HADOOP_MAPRED_HOME/share/hadoop/mapreduce/*,$HADOOP_MAPRED_HOME/share/hadoop/mapreduce/lib/*,    $HADOOP_YARN_HOME/share/hadoop/yarn/*,$HADOOP_YARN_HOME/share/hadoop/yarn/lib/*   </value></property>

And did same changes in my map reduce program.

  configuration.set("yarn.application.classpath",              "{{HADOOP_CONF_DIR}},{{HADOOP_COMMON_HOME}}/share/hadoop/common/*,{{HADOOP_COMMON_HOME}}/share/hadoop/common/lib/*,"                  + " {{HADOOP_HDFS_HOME}}/share/hadoop/hdfs/*,{{HADOOP_HDFS_HOME}}/share/hadoop/hdfs/lib/*,"                  + "{{HADOOP_MAPRED_HOME}}/share/hadoop/mapreduce/*,{{HADOOP_MAPRED_HOME}}/share/hadoop/mapreduce/lib/*,"                  + "{{HADOOP_YARN_HOME}}/share/hadoop/yarn/*,{{HADOOP_YARN_HOME}}/share/hadoop/yarn/lib/*");

My program is running smoothly now. Feel free to ask me details.