[BUG] Description OpenApi Generator 5.0.0 beta gradle-wraper.jar corrupted when copying to a Java Api Client

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator (example)?
• What's the version of OpenAPI Generator used?
• Have you search for related issues/PRs?
• What's the actual output vs expected output?
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Description

corrupts the gradle-wrapper.jar when creating a Java API Client

openapi-generator version

OpenApi Generator 5.0.0 beta

OpenAPI declaration file content or url

Generation Details

Steps to reproduce

I am using these tools at my company Guidewire Software to generate REST Client APIs and when I upgraded from Generator 4.3.1 to 5.0.0 beta the gradle-wrapper.jar it creates is corrupted.
The cause is that jar when copied it is being converted into a string array instead of byte[].

The problem starts in DefaultGenerator
private void generateSupportingFiles(List files, Map<String, Object> bundle) {

if you go to this call
File written = processTemplateToFile(bundle, support.templateFile, outputFilename, shouldGenerate, CodegenConstants.SUPPORTING_FILES);
Then
if (shouldGenerate) {
return this.templateProcessor.write(templateData, templateName, target);
then
TemplateManager
public File write(Map<String, Object> data, String template, File target) throws IOException {
This gets the jar file as a string, it should be bytes
String templateContent = this.engineAdapter.compileTemplate(this, data, template);

Related issues/PRs

Suggest a fix

I have fixed the code in my copy but only as a hack for the one jar. It needs to be managed for all jars like it was in 4.3.1

Reproduce Java API client generation with OpenAPI Generator 5.0.0 beta and compare the gradle-wrapper.jar output with version 4.3.1. Start in DefaultGenerator.generateSupportingFiles and follow processTemplateToFile into TemplateManager.write and the engineAdapter.compileTemplate call; done means generated JAR files remain valid binary content rather than being treated as strings.