The following problems are reported:

• Uses of assert, enum or _ as an identifier
• Uses of the var, yield, or record restricted identifier as a type name
• Unqualified calls to methods named yield
• Modifiers on the requires java.base statement inside of module-info.java
• Redundant semicolons between import statements

Example:

  // This previously legal class does not compile with Java 14,
  // as 'yield' became a restricted identifier.
  public class yield {} 

Fixing these issues timely may simplify migration to future Java versions.