[FLINK-12459][yarn] YarnConfigOptions#CLASSPATH_INCLUDE_USER_JAR shou…

…ld affect the order of classpath between user jars and flink jars

Put user code jars behind the Flink distribution jar when setting
YarnConfigOptions#CLASSPATH_INCLUDE_USER_JAR to "LAST".

This closes apache#8395.

flink-yarn/src/main/java/org/apache/flink/yarn/AbstractYarnClusterDescriptor.java

@@ -786,11 +786,6 @@ public ApplicationReport startAppMaster(
  for (String classPath : systemClassPaths) {
  classPathBuilder.append(classPath).append(File.pathSeparator);
  }
- if (userJarInclusion == YarnConfigOptions.UserJarInclusion.LAST) {
- for (String userClassPath : userClassPaths) {
- classPathBuilder.append(userClassPath).append(File.pathSeparator);
- }
- }
 
  // Setup jar for ApplicationMaster
  Path remotePathJar = setupSingleLocalResource(
@@ -831,6 +826,12 @@ public ApplicationReport startAppMaster(
  paths.add(remotePathConf);
  classPathBuilder.append("flink-conf.yaml").append(File.pathSeparator);
 
+ if (userJarInclusion == YarnConfigOptions.UserJarInclusion.LAST) {
+ for (String userClassPath : userClassPaths) {
+ classPathBuilder.append(userClassPath).append(File.pathSeparator);
+ }
+ }
+
  // write job graph to tmp file and add it to local resource
  // TODO: server use user main method to generate job graph
  if (jobGraph != null) {