DefaultJobParametersConverter throws java.lang.ArrayIndexOutOfBoundsException if input is empty string

[klrs]

Bug description
DefaultJobParamatersConverter class's private parseValue(String encodedJobParameter) method throws java.lang.ArrayIndexOutOfBoundsException if the parameter encodedJobParameter is null or empty.

This causes the batch app started from the command line to not accept empty command line arguments in the format arg1=.

Environment
Java 17
Spring Boot 3.1.4
Spring Batch 5.0.3

Expected behavior
Job parameter should be null or empty.

Minimal Complete Reproducible example

import static org.junit.jupiter.api.Assertions.assertEquals;

import java.util.Properties;

import org.junit.jupiter.api.Test;
import org.springframework.batch.core.converter.DefaultJobParametersConverter;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;

@SpringBootTest
public class Test {

    @Autowired
    DefaultJobParametersConverter converter;

    @Test
    void testConversion() {
        Properties props = new Properties();
        props.put("arg1", "");
        assertEquals("", converter.getJobParameters(props).getString("arg1"));

    }
}

[hwan33]

It seems that it is impossible to distinguish whether its value is null or empty string.
StringUtils.commaDelimitedListToStringArray(encodedJobParameter) returns EMPTY_STRING_ARRAY for both values.

[fmbenhassine]

Thank you for raising this issue! The framework should not fail with an java.lang.ArrayIndexOutOfBoundsException if the value is empty. Job parameters are not designed to accept null values, so in that case the value should be an empty String.