[CAMEL-18856] camel-main - Unable to declare java.util.List bean

• Type: Bug
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 3.18.1, 3.20.0
• Fix Version/s: 3.20.2, 3.21.0, 4.0-M1, 4.0.0
• Component/s: camel-main

Environment

jdk11

• Estimated Complexity: Unknown
• Assignee: Claus Ibsen
• Reporter: Christian Schubert-Huff
• Created: 03/Jan/23 13:04
• Updated: 30/Jan/23 08:59
• Resolved: 04/Jan/23 08:05

Description

I have been unsuccessful in declaring a java.util.List bean. According to camel-main documentation, a List bean should be declared using numeric keys in square brackets:

camel.beans.myprojects[0] = Camel
camel.beans.myprojects[1] = Kafka
camel.beans.myprojects[2] = Quarkus

This does, however, not actually declare a java.util.List, but a java.util.LinkedHashMap, instead.

Again, reproduction is easy:

@Test
public void testBindBeansList() {
    Main main = new Main();
    main.configure().addRoutesBuilder(new MyRouteBuilder());

    // defining a list bean
    main.addProperty("camel.beans.myprojects[0]", "Camel");
    main.addProperty("camel.beans.myprojects[1]", "Kafka");
    main.addProperty("camel.beans.myprojects[2]", "Quarkus");

    main.start();

    CamelContext camelContext = main.getCamelContext();
    assertNotNull(camelContext);

    Object bean = camelContext.getRegistry().lookupByName("myprojects");
    assertNotNull(bean);
    assertInstanceOf(java.util.List.class, bean);

    java.util.List<?> list = (java.util.List<?>) bean;
    assertEquals(3, list.size());
    assertEquals("Camel", list.get(0));
    assertEquals("Kafka", list.get(1));
    assertEquals("Quarkus", list.get(2));

    main.stop();
} 

There is a workaround, which is to use java.util.List#of, which is also more concise, but only possible if using Java 9 or above:

camel.beans.myprojects = #class:java.util.List#of("Camel", "Kafka", "Quarkus")