All the following methods return null value
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URL u = ml1.getResource("java/lang/");
Enumeration e = ml1.getResources("java/lang/");
URL u = ml2.getSystemResource("java/lang/");
e = ml1.getSystemResources("java/lang/");
InputStream u = ml1.getResourceAsStream("java/lang/");
InputStream u = ml1.getSystemResourceAsStream("java/lang/");