public SparkAppJob sparkAppMainClass(String sparkAppMainClass){
		Assert.hasText(sparkAppMainClass, "sparkAppMainClass must not be null nor empty");
		this.sparkAppMainClass = sparkAppMainClass;
		return this;
	}
Sets the package and class of spark app
@param sparkAppMainClass the package and class of the spark app
@return current instance the job.
spring-xd-test-fixtures/src/main/java/org/springframework/xd/test/fixtures/SparkAppJob.java