\nI started building my first Java App Engine Application. I added the plug in to Eclipse and created my first application. Make *sure* to uncheck “Use Google Web Toolkit” unless you really want it. If you are just making a simple servlet – you probably don’t want GWT.<\/p>\n
\nOther than that, it is amazingly simple. When I skimmed the documentation it appeared that not much changed except for the addition of WEB-INF\/appengine-web.xml file – and that was pretty much it. The rest is pretty much pure servlet. Sweet.<\/p>\n
\nWhen you use the Run, option it runs Jetty which puts your application at \/ (i.e. not \/servletname). Somehow, there is no way to stop Jetty when you need to recompile a class and want a full re-deploy. Now I don’t know how well Jetty does with hot-deploy – maybe you just recompile. But for us Tomcat refugees we want to restart once in a while.<\/p>\n
\nHere is how I do it with my Mac:<\/p>\n
\nps -ef | grep geronimo | grep -v grep | awk '{print \"kill \" $2}' | sh -x\n<\/pre>\n\nThen just run your app again from Eclipse.<\/p>\n
\nThe next thing that went wrong is something strange with the Mac Java VM and the harsh security confines of the App Engine – HMAC signing using a native library on the Mac – so you get this sweet traceback:<\/p>\n
\njava.security.AccessControlException: access denied (java.lang.RuntimePermission loadLibrary.keychain)\nat java.security.AccessControlContext.checkPermission(AccessControlContext.java:264)\nat com.google.appengine.tools.development.DevAppServerFactory\nat com.apple.crypto.provider.HmacCore.(HmacCore.java:26)\nat javax.crypto.Mac.init(DashoA12275)\nat net.oauth.signature.HMAC_SHA1.computeSignature(HMAC_SHA1.java:74)\n<\/pre>\n\nNow this is *not* a problem on a deployed Java Application on the Google production environment – but it makes testing kind of less fun. So the workaround is make the following setting:<\/p>\n
\nEclipse -> Propject -> Properties -> Run\/Debug Settings -> select your target -> Edit -> Arguments -> VM Arguments<\/p>\n
\n-D--enable_all_permissions=true\n<\/pre>\n\nNow you might get in trouble because you end up with something working on your mac that fails on the GAE production because it bypasses the Java policies – but at least you can HMAC on your Macintosh.<\/p>\n","protected":false},"excerpt":{"rendered":"
I started building my first Java App Engine Application. I added the plug in to Eclipse and created my first application. Make *sure* to uncheck “Use Google Web Toolkit” unless you really want it. If you are just making a simple servlet – you probably don’t want GWT. Other than that, it is amazingly simple. […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-633","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/www.dr-chuck.com\/csev-blog\/wp-json\/wp\/v2\/posts\/633","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.dr-chuck.com\/csev-blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.dr-chuck.com\/csev-blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.dr-chuck.com\/csev-blog\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.dr-chuck.com\/csev-blog\/wp-json\/wp\/v2\/comments?post=633"}],"version-history":[{"count":1,"href":"https:\/\/www.dr-chuck.com\/csev-blog\/wp-json\/wp\/v2\/posts\/633\/revisions"}],"predecessor-version":[{"id":2740,"href":"https:\/\/www.dr-chuck.com\/csev-blog\/wp-json\/wp\/v2\/posts\/633\/revisions\/2740"}],"wp:attachment":[{"href":"https:\/\/www.dr-chuck.com\/csev-blog\/wp-json\/wp\/v2\/media?parent=633"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.dr-chuck.com\/csev-blog\/wp-json\/wp\/v2\/categories?post=633"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.dr-chuck.com\/csev-blog\/wp-json\/wp\/v2\/tags?post=633"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}