If you try to load the base bundle of a resource bundle family twice, the first load succeds, but the second one fails. The behavior was correct in 1.2.2, but it regressed in 1.3.

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BaseTwice.java
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import java.util.ResourceBundle;
import java.util.Locale;

public class BaseTwice {

    public static void main(String[] args) {
        Locale.setDefault(Locale.US);
        test();
        test();
    }
    
    private static void test() {
        ResourceBundle myResources = ResourceBundle.getBundle("RB", new Locale("
", ""));
        System.out.println(myResources.getString("text"));
    }
}
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RB_en.properties
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text=Got it!


% java13 BaseTwice
Got it!
Exception in thread "main" java.util.MissingResourceException: Can't find bundle for base name RB, locale
        at java.util.ResourceBundle.throwMissingResourceException(ResourceBundle.java:707)
        at java.util.ResourceBundle.getBundleImpl(ResourceBundle.java:604)
        at java.util.ResourceBundle.getBundle(ResourceBundle.java:559)
        at BaseTwice.test(BaseTwice.java:13)
        at BaseTwice.main(BaseTwice.java:9)