### Question:
JavaIdentifierUtils { public static boolean isValidConstantName(String fieldName) { return fieldName.matches("[A-Z][A-Z_]+"); }  static String getJavaClassSimpleName(String javaClassName); static boolean isInnerClass(String javaClassName); static boolean isValidClassName(String className); static int getJavaClassNestingLevel(String javaClassName); static boolean isValidConstantName(String fieldName); static String getPackageName(String javaClassName); static boolean isJavaCoreClass(String javaClassName); static boolean hasSuperclassOrImplementsInterface(Class<?> javaClass, String superJavaClassOrInterfaceName); static Set<String> removeInnerClassesAndInvalidClassNames(Set<String> javaClassNames); static Set<String> javaClassNamesToPackages(Set<String> javaClassNames); static Set<String> removeJavaCoreClassNames(Set<String> javaClassNames);  }### Answer:
@Test public void isValidConstantName() { assertTrue(JavaIdentifierUtils.isValidConstantName("GO_GO_GO")); assertTrue(JavaIdentifierUtils.isValidConstantName("GO")); assertFalse(JavaIdentifierUtils.isValidConstantName("_GO")); assertFalse(JavaIdentifierUtils.isValidConstantName("GO-BLA")); }