Java Language Specification, Version Java SE 21 Edition

4.2.5. The boolean Type and boolean Values

5 Documented Misconceptions

ComparisonWithBooleanLiteral

To test whether an expression is true or false, one must compare it to true or to false

MapToBooleanWithConditionalOperator

To map a boolean expression to a boolean, a conditional operator is necessary

MapToBooleanWithIf

To map a boolean expression to a boolean, an if statement is necessary

NumericToBooleanCoercion

Numeric types can be coerced to boolean

ReferenceToBooleanCoercion

Every reference type can be coerced to boolean