CLDRDisplayNamesTest contains the following logic to report a failure:

System.err.printf("Wrong display name for timezone Etc/GMT-5 : expected GMT+05:00, Actual " + displayName);

https://github.com/openjdk/jdk/blob/8cf0735839727300e446828f4f4a8ef6354a8c7a/test/jdk/java/util/TimeZone/CLDRDisplayNamesTest.java#L133

This call to printf is incorrect, it should either use a format specifier to format displayName, or just call println.

If that line is executed, it can fail with something like:

java.util.UnknownFormatConversionException: Conversion = 'z'
at java.base/java.util.Formatter$FormatSpecifier.conversion(Formatter.java:3117)
at java.base/java.util.Formatter$FormatSpecifier.<init>(Formatter.java:3173)
at java.base/java.util.Formatter$FormatSpecifierParser.parse(Formatter.java:2955)
at java.base/java.util.Formatter.parse(Formatter.java:2854)
at java.base/java.util.Formatter.format(Formatter.java:2784)
at java.base/java.io.PrintStream.implFormat(PrintStream.java:1369)
at java.base/java.io.PrintStream.format(PrintStream.java:1348)
at java.base/java.io.PrintStream.printf(PrintStream.java:1247)
at CLDRDisplayNamesTest.main(CLDRDisplayNamesTest.java:133)