In your IDE, import this project & put a breakpoint on ~/.m2/repository/org/apereo/cas/cas-server-core-api-util/5.3.0-RC1/cas-server-core-api-util-5.3.0-RC1-sources.jar!/org/apereo/cas/CipherExecutor.java:55 with condition value instanceof Integer.
Run USER_ID=$(id -u) docker-compose up and when you see Listening for transport dt_socket at address: 5005, launch your IDE remote Java debugger on port 5005.
You will be stopped at the breakpoint with key = "server.port" and value = 8444 (instance of Integer).
If you step next, you will be able to retrieve the following exception:
java.lang.ClassCastException: java.lang.Integer cannot be cast to java.lang.String
at org.apereo.cas.configuration.support.CasConfigurationJasyptCipherExecutor.decode(CasConfigurationJasyptCipherExecutor.java:20)
at org.apereo.cas.CipherExecutor.lambda$decode$0(CipherExecutor.java:55)
at java.util.Hashtable.forEach(Hashtable.java:879)
at org.apereo.cas.CipherExecutor.decode(CipherExecutor.java:53)
at org.apereo.cas.configuration.DefaultCasConfigurationPropertiesSourceLocator.decryptProperties(DefaultCasConfigurationPropertiesSourceLocator.java:140)
at org.apereo.cas.configuration.DefaultCasConfigurationPropertiesSourceLocator.lambda$loadSettingsByApplicationProfiles$0(DefaultCasConfigurationPropertiesSourceLocator.java:105)
at org.jooq.lambda.Unchecked.lambda$consumer$16(Unchecked.java:646)
at java.util.ArrayList.forEach(ArrayList.java:1255)
at org.apereo.cas.configuration.DefaultCasConfigurationPropertiesSourceLocator.loadSettingsByApplicationProfiles(DefaultCasConfigurationPropertiesSourceLocator.java:100)
at org.apereo.cas.configuration.DefaultCasConfigurationPropertiesSourceLocator.locate(DefaultCasConfigurationPropertiesSourceLocator.java:63)
at org.apereo.cas.configuration.config.CasCoreBootstrapStandaloneConfiguration.locate(CasCoreBootstrapStandaloneConfiguration.java:54)
at org.springframework.cloud.bootstrap.config.PropertySourceBootstrapConfiguration.initialize(PropertySourceBootstrapConfiguration.java:93)
at org.springframework.boot.SpringApplication.applyInitializers(SpringApplication.java:567)
at org.springframework.boot.SpringApplication.prepareContext(SpringApplication.java:338)
at org.springframework.boot.SpringApplication.run(SpringApplication.java:301)
at org.springframework.boot.builder.SpringApplicationBuilder.run(SpringApplicationBuilder.java:134)
at org.apereo.cas.web.CasWebApplication.main(CasWebApplication.java:73)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.springframework.boot.loader.MainMethodRunner.run(MainMethodRunner.java:48)
at org.springframework.boot.loader.Launcher.launch(Launcher.java:87)
at org.springframework.boot.loader.Launcher.launch(Launcher.java:50)
at org.springframework.boot.loader.WarLauncher.main(WarLauncher.java:59)
The same happened with Boolean values defined in application.yml.
An other big problem is that no log can be found explicitely, you must use an IDE to get the stacktrace...