Compiles for me fine in java 8. Earlier versions of Java might need more help return retval == null ? Collections.<String>emptyList() : retval; should work. EDIT This is due to improvements in Java 8 type inference as explained here http://openjdk.java.net/jeps/101 And here’s a blog with the highlights: http://blog.jooq.org/2013/11/25/a-lesser-known-java-8-feature-generalized-target-type-inference/
This should actually compile fine for JDK 7 and 8. Quoting JLS section 14.14.2 (which is the same for the Java 7 specification): The enhanced for statement is equivalent to a basic for statement of the form: for (I #i = Expression.iterator(); #i.hasNext(); ) { {VariableModifier} TargetType Identifier = (TargetType) #i.next(); Statement } Rewriting the … Read more
Oh yes, I have successfully done this on IntelliJ (free Community Edition). Menu > Analyze > Inspect Code… In the result, select “Java language level migration aids > Explicity type can be replaced with <>” Right click, run “Apply Fix ‘Replace with <>’” And you got diamonds. There was a bug about diamond on anomymous … Read more
An instance variable may be changed at any point during the execution of the try-with-resources block. This would break its invariant and prevent the cleanup. Note that the local variable is implictly final, for the same reason. BTW a better question is, why does Java force us to declare a local variable, even if we … Read more
Bug 353467 speaks about “using -XX:-UseSplitVerifier to activate the old verifier”. That is consistent with the JDK TM 6 Adoption Guide which describes that option as: Traditional verifier can be forced with the -XX:-UseSplitVerifier flag. Missing or incorrect StackMapTable attributes for version 50.0 class files can result in VerifyError exceptions. Tools that rewrite bytecode in … Read more
Here is a simple drag and drop example that just sets the file name and location. Drag files to it and it shows their name and location. Once you know that it should be a completely separate matter to actually play the file. It is primarily taken from Oracle’s documentation: https://docs.oracle.com/javafx/2/drag_drop/jfxpub-drag_drop.htm A minimal implementation needs … Read more
Before Java 7: BufferedReader br = new BufferedReader(new FileReader(“foo.txt”)); String line; while ((line = br.readLine()) != null) { System.out.println(line); } add exception handling add closing the stream Since Java 7, there is no need to close the stream, because it implements autocloseable try (BufferedReader br = new BufferedReader(new FileReader(“foo.txt”))) { String line; while ((line = … Read more
While you can write code in Java 7, the Android Systems that run it only support upto Java 6, so 7 features like switch-case on Strings fail. As of Build tools 19, Java 7 is now supported.
Well, there are some obscure things with file systems. I made a few enterprise search crawlers, and somewhere down the road you will notice some strange file system things going on with paths. BTW: these are all implementations of custom (overridden) file systems, so no standard ones, and you can definitely argue for hours on … Read more
The problem is that Java 8 installs a lot of stuff that you don’t really need: \windows\system32 contains Java 8 java.exe, javaw.exe and javaws.exe. Your path probably has system32 near the beginning, so these tend to be run by default. The system path variable starts with C:\programdata\Oracle\Java\javapath. This folder contains java.exe, javaw.exe and javaws.exe as … Read more