From the Java 14 release notes
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The Lookup object produced by MethodHandles::privateLookupIn in this release may not have full privilege access. A lookup which possesses both PRIVATE and MODULE access modes is said to possess full privilege access that can be tested with Lookup::hasFullPrivilegeAccess method. Previously a Lookup returned from MethodHandles::privateLookupIn can be used to look up caller-sensitive methods. In Java SE 14, it may fail to look up caller-sensitive methods if the lookup does not have full privilege access (even it has private access mode).
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