JaCoCo version: 0.8.14
JDK version: 25
OS: Mac
Tools: Maven
Github: https://github.com/Sofiya-Sundaramoorthy/jacoco-0.8.14-switch-statement
Brief description: When upgrading the JaCoCo version from 0.8.12 to 0.8.14 to support JDK25 upgrades, I noticed that the test coverage dropped for a switch statement in combination with forEach.

checkData method takes List as parameter which then loops using forEach to pass data to a switch statement

// method

protected String checkData(List<String> datas) {
        datas.forEach(data -> {
            switch(data) {
                case "a" -> System.out.println("first data");
                case "b" -> System.out.println("second data");
                case "c" -> System.out.println("third data");
                default -> System.out.println("default data");
            };
        });
        return null;
    };

//testcase

@Test
	void testData() {
		var application = new SwitchStatementApplication();
		var result1 = application.checkData(List.of("a", "b", "c", "d"));
		assertNull(result1);
	}

The minimal reproducible code is in the github repo https://github.com/Sofiya-Sundaramoorthy/jacoco-0.8.14-switch-statement

Note: The switch statement takes parameter of type String which gives 78% test coverage. However, when passing parameter type of Int the coverage is 100%

Expected behaviour: The combination of forEach + switch (parameter type as String) should produce 100% test coverage

Actual behaviour: The combination of forEach + switch (parameter type as String) produces 78% test coverage

Please refer the screenshots

JaCoCo 0.8.12 with JDK21

JaCoCo 0.8.14 with JDK25