How to set flink parallelism in pure java (IDEA)

Question

I am using following scala code to run my flink streaming job

val mystream = StreamExecutionEnvironment.getExecutionEnvironment
    mystream.addSource(new mySource(params))
      .map(new myMap(params))
      .addSink(new mySink(params)).setParallelism(1)
    mystream.setParallelism(1)
    mystream.execute("My Streaming")

when I use flink run -p 1, the parallelism is 1(do not know whether -p works or the code works). when I use pure java to run, (in IDEA I suppose it runs in pure java), the parallelism is usually 5, which shows my code does not work. How to control it?

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as top answer suggested, following code also does not work, still has parellelism of 5.

val mystream = StreamExecutionEnvironment.getExecutionEnvironment
    mystream.addSource(new mySource(params))
      .map(new myMap(params))
      .addSink(new mySink(params))
    mystream.setParallelism(1)
    mystream.execute("My Streaming")

Answer 1

You set the default parallelism on the environment.

val env = StreamExecutionEnvironment.getExecutionEnvironment
env.setParallelism(1)
env.addSource(...)

Using .addSink(new mySink(params)).setParallelism(1) overrides that default parallelism for the specific operator.