Generating client for spec=containers/containers.yaml lang=java -> generated-clients/containers/java
[main] INFO  o.o.codegen.DefaultGenerator - Generating with dryRun=false
[main] INFO  o.o.c.ignore.CodegenIgnoreProcessor - No .openapi-generator-ignore file found.
[main] INFO  o.o.codegen.DefaultGenerator - OpenAPI Generator: java (client)
[main] INFO  o.o.codegen.DefaultGenerator - Generator 'java' is considered stable.
[main] INFO  o.o.c.languages.AbstractJavaCodegen - Environment variable JAVA_POST_PROCESS_FILE not defined so the Java code may not be properly formatted. To define it, try 'export JAVA_POST_PROCESS_FILE="/usr/local/bin/clang-format -i"' (Linux/Mac)
[main] INFO  o.o.c.languages.AbstractJavaCodegen - NOTE: To enable file post-processing, 'enablePostProcessFile' must be set to `true` (--enable-post-process-file for CLI).
[main] ERROR o.o.codegen.DefaultGenerator - An exception occurred in OpenAPI Normalizer. Please report the issue via https://github.com/openapitools/openapi-generator/issues/new/: 
[main] ERROR o.o.codegen.DefaultGenerator - An exception occurred in OpenAPI Normalizer. Please report the issue via https://github.com/openapitools/openapi-generator/issues/new/: 
java.lang.NullPointerException: Cannot invoke "io.swagger.v3.oas.models.media.Schema.get$ref()" because "schema" is null
	at org.openapitools.codegen.OpenAPINormalizer.normalizeSchema(OpenAPINormalizer.java:699)
	at org.openapitools.codegen.OpenAPINormalizer.normalizeHeaders(OpenAPINormalizer.java:561)
	at org.openapitools.codegen.OpenAPINormalizer.normalizeResponse(OpenAPINormalizer.java:545)
	at org.openapitools.codegen.OpenAPINormalizer.normalizeResponses(OpenAPINormalizer.java:533)
	at org.openapitools.codegen.OpenAPINormalizer.normalizePaths(OpenAPINormalizer.java:426)
	at org.openapitools.codegen.OpenAPINormalizer.normalize(OpenAPINormalizer.java:355)
	at org.openapitools.codegen.DefaultGenerator.configureGeneratorProperties(DefaultGenerator.java:266)
	at org.openapitools.codegen.DefaultGenerator.generate(DefaultGenerator.java:1277)
	at org.openapitools.codegen.cmd.Generate.execute(Generate.java:535)
	at org.openapitools.codegen.cmd.OpenApiGeneratorCommand.run(OpenApiGeneratorCommand.java:32)
	at org.openapitools.codegen.OpenAPIGenerator.main(OpenAPIGenerator.java:66)
[main] INFO  o.o.c.languages.AbstractJavaCodegen - Processing operation post-containers-with-container-id
[main] INFO  o.o.c.languages.AbstractJavaCodegen - Processing operation delete-containers-with-container-id
[main] INFO  o.o.c.languages.AbstractJavaCodegen - Processing operation delete-containers-with-container-id-with-packages
[main] INFO  o.o.c.languages.AbstractJavaCodegen - Processing operation post-containers
[main] INFO  o.o.c.languages.AbstractJavaCodegen - Processing operation post-manifest

Error:  COMPILATION ERROR : 
Error:  /home/runner/work/usps-api/usps-api/generated-clients/containers/java/src/main/java/org/openapitools/client/model/MailingDateOptions.java:[105,33] error: cannot find symbol
  symbol:   method validateJsonElement(JsonElement)
  location: class LocalDate
Error:  /home/runner/work/usps-api/usps-api/generated-clients/containers/java/src/main/java/org/openapitools/client/model/MailingDateOptions.java:[117,38] error: cannot find symbol
  symbol:   method validateJsonElement(JsonElement)
  location: class OffsetDateTime
Error:  /home/runner/work/usps-api/usps-api/generated-clients/containers/java/src/main/java/org/openapitools/client/model/MailingDateOptions.java:[229,21] error: cannot find symbol
  symbol:   method validateJsonElement(JsonElement)
  location: class LocalDate
Error:  /home/runner/work/usps-api/usps-api/generated-clients/containers/java/src/main/java/org/openapitools/client/model/MailingDateOptions.java:[237,26] error: cannot find symbol
  symbol:   method validateJsonElement(JsonElement)
  location: class OffsetDateTime
Error:  Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:3.8.1:compile (default-compile) on project openapi-java-client: Compilation failure: Compilation failure: 
Error:  /home/runner/work/usps-api/usps-api/generated-clients/containers/java/src/main/java/org/openapitools/client/model/MailingDateOptions.java:[105,33] error: cannot find symbol
Error:    symbol:   method validateJsonElement(JsonElement)
Error:    location: class LocalDate
Error:  /home/runner/work/usps-api/usps-api/generated-clients/containers/java/src/main/java/org/openapitools/client/model/MailingDateOptions.java:[117,38] error: cannot find symbol
Error:    symbol:   method validateJsonElement(JsonElement)
Error:    location: class OffsetDateTime
Error:  /home/runner/work/usps-api/usps-api/generated-clients/containers/java/src/main/java/org/openapitools/client/model/MailingDateOptions.java:[229,21] error: cannot find symbol
Error:    symbol:   method validateJsonElement(JsonElement)
Error:    location: class LocalDate
Error:  /home/runner/work/usps-api/usps-api/generated-clients/containers/java/src/main/java/org/openapitools/client/model/MailingDateOptions.java:[237,26] error: cannot find symbol
Error:    symbol:   method validateJsonElement(JsonElement)
Error:    location: class OffsetDateTime
Error:  -> [Help 1]
Error:  
Error:  To see the full stack trace of the errors, re-run Maven with the -e switch.
Error:  Re-run Maven using the -X switch to enable full debug logging.
Error:  
Error:  For more information about the errors and possible solutions, please read the following articles:
Error:  [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoFailureException
Error: Process completed with exit code 1.