Reports ternary expression with the form `condition ? literalBoolean : foo` or `condition ? foo : literalBoolean`. These expressions can be simplified as follows: * `condition ? true : expr` simplifies to `condition || expr` * `condition ? false : expr` simplifies to `!condition && expr` * `condition ? expr : true` simplifies to `!condition || expr` * `condition ? expr : false` simplifies to `condition && expr` SimplifiedTernary (Priority: 1, Ruleset: Design) https://docs.pmd-code.org/snapshot/pmd_rules_java_design.html#simplifiedternary

Position literals first in all String comparisons, if the second argument is null then NullPointerExceptions can be avoided, they will just return false. Note that switching literal positions for compareTo and compareToIgnoreCase may change the result, see examples. Note that compile-time constant strings are treated like literals. This is because they are inlined into the class file, are necessarily non-null, and therefore cannot cause an NPE at runtime. LiteralsFirstInComparisons (Priority: 1, Ruleset: Best Practices) https://docs.pmd-code.org/snapshot/pmd_rules_java_bestpractices.html#literalsfirstincomparisons

Position literals first in all String comparisons, if the second argument is null then NullPointerExceptions can be avoided, they will just return false. Note that switching literal positions for compareTo and compareToIgnoreCase may change the result, see examples. Note that compile-time constant strings are treated like literals. This is because they are inlined into the class file, are necessarily non-null, and therefore cannot cause an NPE at runtime. LiteralsFirstInComparisons (Priority: 1, Ruleset: Best Practices) https://docs.pmd-code.org/snapshot/pmd_rules_java_bestpractices.html#literalsfirstincomparisons

Reports fields which may be converted to a local variable. This is so because in every method where the field is used, it is assigned before it is first read. Hence, the value that the field had before the method call may not be observed, so it might as well not be stored in the enclosing object. Limitations: * We can only check private fields for now. * The rule is not aware of threading, so it may cause false positives in concurrent code. Such FPs are best handled by suppression (see also the `ignoredAnnotations` property). SingularField (Priority: 1, Ruleset: Design) https://docs.pmd-code.org/snapshot/pmd_rules_java_design.html#singularfield