I know Jobs can be submit to JobManager by flink or flink.bat. I wanna know whether Flink provides Java API to submit jobs to JobManager?
Yes. Depending on the type of cluster you want to connect, there are several implementations of the ClusterClient (https://ci.apache.org/projects/flink/flink-docs-release-1.3/api/java/org/apache/flink/client/program/ClusterClient.html).
It can run jobs either in a blocking (synchronous) or detached (asynchronous) fashion. One way of deploying a job is to provide a PackagedProgram, which consists of a JAR file with a Main Class and several supporting JAR files (additional libraries required specifically for the job).