It never occurred to me I should write a Java URL shortener service with Dropwizard and Redis. Not because of Dropwizard or Redis, I just didn’t see why I should write a Java URL shortener at all. That is until I read the blog post URL shortener service in 42 lines of code in… Java […]
WSDL and its mapping to Java never fail to puzzle me. The other day I was confused about OUT parameters (holders) vs. return types. CXF‘s wsdl2java produced those ugly and terrible to work methods with OUT parameters in one case and natural methods with return types in other cases. Here’s why. First the obvious…”If there […]
JPA batch inserts (aka bulk inserts) may seem trivial at first. However, if you’re not careful you won’t see the performance gains you expect even though your application works “just fine”. If you follow the below guidelines your JPA batch inserts should be blazingly fast, though. JPA batch inserts with Hibernate All the material presented […]
Here’s a pretty neat approach to add AccessDescisionVoters to the default AccessDescisionManager in Spring Security:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 | /** * This BeanPostProcessor adds all {@link AccessDecisionVoter}s that are set with * {@link #setAdditionalAccessDecisionVoters(List)} to beans that are instances of {@link AffirmativeBased}. This is the * default {@link AccessDecisionManager} implementation that the spring security namespace handler creates. * <p> * * The configuration could look like: * * <pre> * {@code * <bean id="voterAdder"> * <property name="additionalAccessDecisionVoters"> * <list> * <bean /> * </list> * </property> * </bean> * } * </pre> */ @Component public class VoterAdder implements BeanPostProcessor { private List<AccessDecisionVoter> additionalAccessDecisionVoters; public void setAdditionalAccessDecisionVoters(List<AccessDecisionVoter> additionalAccessDecisionVoters) { this.additionalAccessDecisionVoters = additionalAccessDecisionVoters; } @Override public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException { return bean; } @Override public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException { if (bean instanceof AffirmativeBased) { AffirmativeBased dm = (AffirmativeBased) bean; additionalAccessDecisionVoters.addAll(dm.getDecisionVoters()); dm.setDecisionVoters(additionalAccessDecisionVoters); } return bean; } } |
Source: http://forum.springsource.org/showthread.php?116830-How-to-add-voters-to-the-default-accessDecisionManager&s=1a6d05dedb0342570b900141a6d53d2e&p=386079#post386079
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 | final Image image = ...; final ByteArrayOutputStream baos = new ByteArrayOutputStream(); try { final BufferedImage bufferedImage = createBufferedImageFrom(image); ImageIO.write(bufferedImage, "png", baos); } finally { IOUtils.closeQuietly(baos); } return baos.toByteArray(); private BufferedImage createBufferedImageFrom(final Image image) { if (image instanceof BufferedImage) { return (BufferedImage) image; } else { final BufferedImage bi = new BufferedImage(image.getWidth(null), image.getHeight(null), BufferedImage.TYPE_INT_RGB); final Graphics2D g2 = bi.createGraphics(); g2.drawImage(image, 0, 0, null); return bi; } } |
If you don’t want to make use of IOUtils from Apache Commons Lang, you should you know, the code in the finally block would be something like
1 2 3 4 5 6 7 | try { if (baos != null) { baos.close(); } } catch (IOException ioe) { // ignore } |
dnsjava to resolve whatever address request.getRemoteAddr() would return. This worked very well in most cases. However, in some cases I would see something like: [quote]java.net.UnknownHostException: Invalid address: fe80::1d9:b65a:ed86:7940%11[/quote] Not being much of a networking expert I was puzzled about the ‘%11’. Once again superuser.com came to rescue: http://superuser.com/questions/99746/why-is-there-a-in-the-ipv6-address
At the technical panel discucssion on Friday morning at Devoxx there was the interesting question “Does Oracle’s corporate culture stand in the way of success for Java?”. Even more interesting was the answer from either Brian Goetz or Mark Reinold (don’t remember), both big wigs at Oracle… “I think Java became a success despite Sun’s […]
Creating a DDL in the Maven build with the hibernate3-maven-plugin fails if you explicitly configure an array of javax.persistence.CascadeType values in your JPA annotations. The stacktrace is similar to
1 2 3 4 5 6 7 | javax.persistence.PersistenceException: [PersistenceUnit: spontacts] Unable to configure EntityManagerFactory at org.hibernate.ejb.Ejb3Configuration.configure(Ejb3Configuration.java:265) at org.codehaus.mojo.hibernate3.configuration.JPAComponentConfiguration.createConfiguration(JPAComponentConfiguration.java:28) ... Caused by: java.lang.ArrayStoreException: sun.reflect.annotation.EnumConstantNotPresentExceptionProxy at sun.reflect.annotation.AnnotationParser.parseEnumArray(AnnotationParser.java:673) at sun.reflect.annotation.AnnotationParser.parseArray(AnnotationParser.java:462) |
Once I realized what the actual cause is, the fix was simple. Turns out that the CascadeType is not in the classpath when Maven runs […]
Assume entity A has a one-to-many relationship to B. So, you’d have a method like A#getBs(). However, sometimes you might/will only need the number of Bs and not the entities themselves i.e. you need the count. However, if you called A#getBs()#getSize() you’d effectively initialize the collection and thereby loading entities into memory for no reason. […]
When you need to support self-signed SSL certificates in your Apache HttpClient based application you can use the contributed EasySSLProtocolSocketFactory as described in the HttpClient docs. Instead of using HttpClient’s HostConfiguration object directly you’d modify its protocol socket factory in your code like so:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 | ... if (config.isAllowSelfSignedCertificates()) { ProtocolSocketFactory factory = new EasySSLProtocolSocketFactory(); try { URI uri = new URI(config.getBaseUrl()); int port = uri.getPort(); if (port == -1) { port = 443; } Protocol easyHttps = new Protocol(uri.getScheme(), factory, port); hostConfiguration.setHost(uri.getHost(), port, easyHttps); } catch (URISyntaxException e) { throw new IOException("could not parse URI " + config.getBaseUrl(), e); } } ... |
Somewhere you’d instantiate a HttpClient object. Then you get its […]