java-6

问题 I was reading the Java SE 6 specs and then found some confusing stuff that a I can't reproduce: A type variable may not at the same time be a subtype of two interface types which are different parameterizations of the same generic interface. I wrote the following code: interface Odd {} interface Even {} interface Strange extends Odd, Even {} interface InterfaceOne<O extends Odd, E extends Even> {} interface InterfaceTwo<O extends Odd, E extends Even> extends Odd, Even {} public class Test {

问题 It may happen a thread is waiting on an object monitor and never wakes up because no other thread is notifying it (which of course is a bug...). Using the jstack utility I see all threads and their name and status. Is it possible to interrupt a thread (so it throws an InterruptedException ) from the command line or anyway from within a different process? I know about the https://github.com/jglick/jkillthread utility but that one simply kills the thread and I need the thread to be interrupted

问题 I just installed Java 1.6 on my OSX and everything works brilliantly, except that Eclipse refuses to start. It puts up a huge prompt from which I can't copy/paste, but it's clearly stating that it wants to be using Java 1.5 and can't find it anymore. I don't see anything in its configuration files about which version of Java it should be looking for. Has anyone dealt with this? Thanks in advance. 回答1: on /Applications/Eclipse/Eclipse.app right click and choose "Show Package Contents" open

问题 i am using jdk1.6. I configureg Xmx = 2G, Xms= 2G, NewSize = MaxNewSize = 660m I enable verbose gc. I see this which I am not undertsnaidng: PSYoungGen total 608256K, used 32440K eden space 540672K, 6% used from space 67584K, 0% used to space 67584K, 0% used According to my configuration YoungGen size is 675840MB. Because younGen = Eden + two survivor spaces, GC log saying that my YoungGen size = 608256K which is not what i've configured. Also if I add Eden space and two survivor spaces I am

问题 We're currently using ojdbc14.jar, should we be using ojdbc6.jar ? Update: Oracle 10g being used 回答1: If you're working with java6, you can (and should) use ojdbc6.jar if it is compatible with your database. Resources : oracle.com - JDBC drivers 回答2: Short answer - yes, you should. Long answer - look at compatibility tables in Oracle JDBC FAQ: Which JDBC drivers support which versions of Oracle Database? Which JDBC drivers support which versions of Javasoft's JDK? For JDK 1.6 and Oracle 10g

问题 I want an object that can be created by any thread, but the moment a thread calls myObject.use() it can only be used by that thread until myObject.release() is called. I don't want to force the developers to have to wrap all method calls for this object/class in synchronized blocks (which I know could be used to approximate this functionality) as that's likely to lead to misuse of the object if they forget to wrap all calls from myObject.use() to myObject.release() in the same synchronized

问题 After installing the Java for OS X 2012-006 update, the Java Preferences app, for configuring applets and, more importantly for me, Java Web Start apps has gone. The tech note about this update says: This update also removes the Java Preferences application, which is no longer required to configure applet settings. If it's no longer required, what has replaced it, or how do I get back the same functionality? One of the things I used to be able to do was configure when / how the Java Console

问题 When i tried to deploy the Java 6 application in App engine. I got error like Java 6 applications are prevented from being deployed to Google App Engine from any version of the SDK, including older ones. If you need to continue to deploy Java 6 applications for compatibility reasons, you can request that your application be whitelisted for Java 6 deployment by visiting link. Then i changed java version 1.7 in project settings. Even after, app engine deployment throw same error. How to fix

问题 Say I have the following XML and Java code respectively: <foo> My text content </foo> @XmlRootElement( name="foo" ) public static class Foo { // This is where I want to see "My text content" stored private String text; // getters and setters } When I tried marshalling the XML, my Foo instance doesn't get its text property populated with value from the inner text of my foo element in the given XML. How do I solve this? 回答1: You can use the @XmlValue annotation. @XmlValue public String getText(

问题 Here I am trying to download multiple files one after another: Environment - Java 1.6 public List<Attachment> download(List<Attachment> attachments) { for(Attachment attachment : attachments) { attachment.setDownStatus("Failed"); String destLocation = "C:\Users\attachments"; try { String attUrl = attachment.getUrl(); String fileName = attachment.getFileName(); URL url = new URL(attUrl); File fileLocation = new File(destLoc, fileName); FileUtils.copyURLToFile(url, fileLocation); if