Fix ClassCastException in RunIdIncrementer

Before this commit, the RunIdIncrementer was failing
with a ClassCastException if the run.id parameter is
not passed as a Long.

This commit makes the RunIdIncrementer more liberal
in what it accepts by trying to parse the parameter
to a Long.

Resolves #3799

spring-batch-core/src/test/java/org/springframework/batch/core/launch/support/RunIdIncrementerTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2006-2013 the original author or authors.
+ * Copyright 2006-2020 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -24,6 +24,7 @@ import org.springframework.batch.core.JobParametersBuilder;
 /**
  * @author Dave Syer
  * @author Michael Minella
+ * @author Mahmoud Ben Hassine
  *
  */
 public class RunIdIncrementerTests {
@@ -51,4 +52,25 @@ public class RunIdIncrementerTests {
 		assertEquals(1, next.getLong("foo").intValue());
 	}
 
+	@Test
+	public void testGetNextWhenRunIdIsString() {
+		// given
+		JobParameters parameters = new JobParametersBuilder()
+				.addString("run.id", "5")
+				.toJobParameters();
+
+		// when
+		JobParameters next = this.incrementer.getNext(parameters);
+
+		// then
+		assertEquals(Long.valueOf(6), next.getLong("run.id"));
+	}
+
+	@Test(expected = IllegalArgumentException.class)
+	public void testGetNextWhenRunIdIsInvalidString() {
+		this.incrementer.getNext(new JobParametersBuilder()
+				.addString("run.id", "foo")
+				.toJobParameters());
+	}
+
 }