[JAVA] Enum character escaping bug

Description

Java Enum Codegen escapes both + (plus) and - (minus) with "_". In some cases, it can cause duplicated Enum names that are prohibited by JLS.

Swagger-codegen version

Online Editor

Swagger declaration file content or url

  definitions: 
    BuggedCodeGen: 
      type: "object"
      properties: 
        timeZone:
          type: "string"
          enum:
          - "Etc/GMT+1"
          - "Etc/GMT-1"

Results in:

public enum TestEnum {
    GMT_1("Etc/GMT+1"),
    GMT_1("Etc/GMT-1");
    // ...
}

Suggest a Fix

Replace + with PLUS and - with MINUS

Start by tracing the Java enum code generation path for the provided YAML declaration and inspect how plus and minus characters are escaped. Reproduce the duplicate constants GMT_1 and GMT_1, then verify that the generated enum uses distinct names such as PLUS and MINUS and compiles successfully.