java-14

问题 I am reading the documentation of Records and don't understand the term "shallowly immutable". What do we mean by shallowly immutable ? And if it's immutable why we need a copy constructor? Why two "Hello Worlds!"? For all record classes, the following invariant must hold: if a record R's components are c1, c2, ... cn, then if a record instance is copied as follows: R copy = new R(r.c1(), r.c2(), ..., r.cn()); // copy constructor ? then it must be the case that r.equals(copy) . 回答1: Shallowly

问题 I really like the addition of records in Java 14, at least as a preview feature, as it helps to reduce my need to use lombok for simple, immutable "data holders". But I'm having an issue with the implementation of nullable components. I'm trying to avoid returning null in my codebase to indicate that a value might not be present. Therefore I currently often use something like the following pattern with lombok. @Value public class MyClass { String id; @Nullable String value; Optional<String>

问题 I get the the pop-up Build failed debugger for java. I previously had trouble running java after upgrading from JDK 8 to JDK 14 but now I can but I can't run the commands javac and java from the integrated terminal of VScode . I have tried clearing the WorkspaceStorage but it isn't working. I am not really familiar with all this; any help is appreciated. Edit: The java commands are now working by implementing this. The debugger is not. 来源： https://stackoverflow.com/questions/63729693/build

问题 There is a message Project has been compiled by a more recent version of the Java Runtime (class file version 57.0), this version of the Java Runtime only recognizes class file versions up to 52.0 I googled "JRE required for JDK 14" and there is no download to be found. In my Java control panel on Windows 10, it says I have the latest version of the Java platform. I cannot downgrade the JDK on my project since I am using a library which was completely compiled on Java 14. How (and where) does

问题 Cannot rerun JPackage installer if already installed, second time just seems to exit without warning, is this correct behaviour on Windows ? You may ask why I want to do this anyway? Well in my case I am trying to build a JPackage installer for my Java application, so I am building it installing it, then tweaking the settings, rebuilding it and try to reinstall. It took me some time to work out that I couldn't not reinstall it unless i uninstall the first installation (using Control Panel,

问题 I have installed java 14 in my system at following location. C:\Program Files\Java\jdk-14.0.1 but on running java -version it is still pointing to java version "1.8.0_251" . How do I change that to point to Java 14. I have set my JAVA_HOME to C:\Program Files\Java\jdk-14.0.1\bin and appended the same to Path of system variables but still it is showing the older version. Why is it happening, a little help will be deeply appreciated. Thanks 回答1: I found the problem, the Path system variable had

问题 I am getting a "javax.net.ssl.SSLException: Connection reset" for this piece of code ReadableByteChannel rbc = Channels.newChannel(url.getInputStream()); but only when running under a Java 14 JRE built with jlink from Open JDK 14. The code executes just fine if I point to the full JDK. I suspect something is missing in the JRE, but what is it and why did jlink not copy the missing files accross? My jlink command based on jdeps is as follows: "C:\Program Files\Java\jdk-14\bin\jlink.exe" --no

问题 I am getting a "javax.net.ssl.SSLException: Connection reset" for this piece of code ReadableByteChannel rbc = Channels.newChannel(url.getInputStream()); but only when running under a Java 14 JRE built with jlink from Open JDK 14. The code executes just fine if I point to the full JDK. I suspect something is missing in the JRE, but what is it and why did jlink not copy the missing files accross? My jlink command based on jdeps is as follows: "C:\Program Files\Java\jdk-14\bin\jlink.exe" --no

来源： https://stackoverflow.com/questions/63779210/java-14-verifyerror-from-innocuous-statement

来源： https://stackoverflow.com/questions/63779210/java-14-verifyerror-from-innocuous-statement