Debugging Spring REST bad request 400 codes

This happens way too often: you POST or PUT something to a Spring @RestController and Spring only tells you that there is a bad request, HTTP 400 code; no further explanations, no logs, no exceptions. Spring logs the error cause under the category "org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod" so you can enable logging for that in your log4j.properties: log4j.logger.org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod=DEBUG,stdout … Continue reading Debugging Spring REST bad request 400 codes

End-to-end testing Java web applications with an embedded Tomcat

 In this instalment on assembly testing [1] I'll talk about how automated system tests run over my Java web applications. The set-up is rather cheap, not very labour-intensive and can incrementally evolve from a simple assembly test (aka smoke test) to a full-fledged system test. Since this post is rather concrete naming tools and frameworks, … Continue reading End-to-end testing Java web applications with an embedded Tomcat

SSLHandshakeException: unsupported certificate

When: loading client certificates from a custom keystore Reason: multiple certificates for the same domain but different purposes, e.g. one certificate handles email authentication, the other authenticates the user against a web server Solution: either fix the buggy code that selects the wrong certificate from the keystore or make sure only one certificate per domain … Continue reading SSLHandshakeException: unsupported certificate

Spring MVC REST controller says 406 when emails are part URL path

You've got this Spring @RestController and mapped a URL that contains an email as part of the URL path. You cunningly worked around the dot truncation issue [1] and you are ready to roll. And suddenly, on some URLs, Spring will return a 406 [2] which says that the browser requested a certain content type … Continue reading Spring MVC REST controller says 406 when emails are part URL path

Fauxjsp: productive JSP development

Important note: This post is not being updated. For up-to-date information refer to the project repository: https://github.com/ggeorgovassilis/fauxjsp/ About JSP In this post I'll present a new open source project I'm currently working on, fauxjsp [1] which re-implements JSP in a way that is more robust and faster for developers. It is intended for development, where … Continue reading Fauxjsp: productive JSP development

Reactive programming for Java, revisited

Abstract Rewritten on 15 January 2015 In this post I'll talk about the problems callbacks introduce into the readability of asynchronous Java programs. I'll also discuss an implementation of method pointers for Java which aids the transformation of a callback-style program into a linear program flow, greatly increasing readability while still being a 100% asynchronous … Continue reading Reactive programming for Java, revisited

Tomcat/Scala: invalid byte tag in constant pool: 110

When deploying a Scala application on Tomcat 7 I got this weird error: invalid byte tag in constant pool: 110 from Tomcat's annotation scanning in the scala utils jar. There is this bug report that claims it's fixed, but it seems to still happen wit 7.0.53. Since the application doesn't rely on Tomcat's annotation scanning, … Continue reading Tomcat/Scala: invalid byte tag in constant pool: 110

When scala unitests won’t run in the Scala IDE with Maven

Stupid problem: scala unit tests / scalatest tests suddenly won't run after a failed maven build claiming with a ClassNotFoundException that the test class doesn't exist. I believe this to be a weird class loading issue where Eclipse doesn't include unit tests into the classpath. The very, very sad workaround is: run a successful maven … Continue reading When scala unitests won’t run in the Scala IDE with Maven

LocalContainerEntityManagerFactoryBean, Hibernate and superflous tables created in wrong database

TL;DR Hibernate's (3.2-3.4) JPA implementation will pick up hbm files on it's own when it should be looking only at persistence.xml, thus: - loading more entities that it should - loading the wrong entities - performing schema updates in the wrong database This one annoyed me plenty and took a great deal of debugging to … Continue reading LocalContainerEntityManagerFactoryBean, Hibernate and superflous tables created in wrong database