Don't cache URL when loading junit-platform.properties contents

[sormuras]

Today, the code in the launcher uses the convenient input stream accessor openStream() provided by the URL class:

junit5/junit-platform-launcher/src/main/java/org/junit/platform/launcher/core/LauncherConfigurationParameters.java

Lines 66 to 68 in efdb9fd

	try (InputStream inputStream = configFileUrl.openStream()) {
	props.load(inputStream);
	}

This implicitly caches an underlying JAR file for the current VM, if the junit-platform.properties file is located in a JAR file. On Windows, that means a lock is held by the VM until its associated reference is garbage collected.

When, for example, testing the launcher framework within a test method that prepares a custom class-path or module-path with generated JAR files in a temporary directory, that temporary directory can't be deleted on Windows, due the lock of the cached JAR file reference.

Deliverables

• Use the following code to prevent caching of an underlying JAR file:

URLConnection urlConnection = configFileUrl.openConnection();
urlConnection.setUseCaches(false);
try (InputStream inputStream = urlConnection.getInputStream()) {
 props.load(inputStream);
}

[sormuras]

Related JBS issue JDK-8224794

[sormuras]

Reopened for cherry-picking into 5.6.1

[sormuras]

🍒 picked.