Reports import statements that can be removed. They are either unused, duplicated, or the members they import are already implicitly in scope, because they're in java.lang, or the current package. If some imports cannot be resolved, for instance because you run PMD with an incomplete auxiliary classpath, some imports may be conservatively marked as used even if they're not to avoid false positives. UnnecessaryImport (Priority: 4, Ruleset: Code Style) https://docs.pmd-code.org/pmd-doc-7.4.0/pmd_rules_java_codestyle.html#unnecessaryimport