jshell

问题 I'm trying to use JShell provided by JDK11 to run some simple command. But when I type: jshell>System.out.println("Hello World!"); It gives me the error: Exception in thread "main" java.lang.NullPointerException: charsetName at java.base/java.lang.String.<init>(String.java:464) at java.base/java.lang.String.<init>(String.java:537) at jdk.internal.le/jdk.internal.jline.extra.AnsiInterpretingOutputStream.write(AnsiInterpretingOutputStream.java:92) at java.base/java.io.OutputStream.write

问题 I'm trying to use JShell provided by JDK11 to run some simple command. But when I type: jshell>System.out.println("Hello World!"); It gives me the error: Exception in thread "main" java.lang.NullPointerException: charsetName at java.base/java.lang.String.<init>(String.java:464) at java.base/java.lang.String.<init>(String.java:537) at jdk.internal.le/jdk.internal.jline.extra.AnsiInterpretingOutputStream.write(AnsiInterpretingOutputStream.java:92) at java.base/java.io.OutputStream.write

问题 I want to create JShell programmatically when the security manager is set before. However, this causes an access control exception. Without the security manager set the code works correctly. I thought that the Java platform modules have all permissions by default. What shall I set or configure to create JShell without any exception caused by the security manager? Below is the code that I tried. I use OpenJDK 12.0.2. The policy file: grant codeBase "file:${user.dir}/-" { permission java

问题 So I was fiddling some code in jshell, but it started crashing when I pressed Tab. int[] a = new int[]{1, 2, 5, 0, -1} In my next statement, when I type A-r-r-a, then (Tab) to autocomplete to Array and get options, it crashes with Error on input: java.io.IOException: Resource temporarily unavailable Does anyone know how to fix this? EDIT: I'm using Elementary OS Juno. It is a distro based on Ubuntu 18.04 回答1: I believe this may be a result of https://bugs.launchpad.net/ubuntu/+source/linux/

问题 How to find the type of a variable or Expression Result in JShell. Was experimenting Bitwise Operators in Java jshell> byte b=5<<-1; | Error: | incompatible types: possible lossy conversion from int to byte | byte b=5<<-1; | ^---^ jshell> 5<<-1 $2 ==> -2147483648 jshell> Is there an alternative like Python type(5<<-1) to find the result type of expression or variable in Jshell. 回答1: Just figured out it can be solved by setting the feedback mode. /set feedback verbose Reference https://docs

问题 I am using JShell to test a library for which I made classes, sources, and javadoc available through the class path like so: jshell --class-path library-javadoc.jar:library-sources.jar:library-jar-with-dependencies.jar Still, when double tab after a documented Java identifier I receive: <no documentation found> How does JShell expect the documentation? 回答1: Seems to be a unresolved issue: https://bugs.openjdk.java.net/browse/JDK-8186876 来源： https://stackoverflow.com/questions/47245854/how-to

问题 As per the documentation, There’s also the option to load a script on startup, including some special predefined options. These are specified using the —startup flag, passing in either a filename or one of: DEFAULT – load the default behavior. This acts the same as if this is not specified at all JAVASE – Imports all Java SE packages by default PRINTING – defines the functions print, println and printf for use But, when i started the jshell with DEFAULT, JAVASE or PRINTING options, i could

问题 As per the documentation, There’s also the option to load a script on startup, including some special predefined options. These are specified using the —startup flag, passing in either a filename or one of: DEFAULT – load the default behavior. This acts the same as if this is not specified at all JAVASE – Imports all Java SE packages by default PRINTING – defines the functions print, println and printf for use But, when i started the jshell with DEFAULT, JAVASE or PRINTING options, i could

问题 JShell is a Java REPL that is scheduled to be released alongside Java 9; however, there is an open beta for it. If I create an infinite loop in JShell (Project Kulla) by typing: -> while(true) {} JShell will loop forever. Short of completely quitting JShell, is there a way to stop an individual line of code while it's running in JShell (after you have already begun evaluation of the code)? 回答1: Actually there is a way. Just hit CTRL + c : -> while(true) {} Killed. -> It'll kill the loop and

问题 Just exploring new release of Java, its new module system, and playing with jshell as well. Probably my question doesn't have too much sense, but I am just curious. So I came up with the question: Is there any way to create a module in jshell? Or module can be only created in module-info.java ? 回答1: Modules cannot be created using JShell currently and it is not a Goal of JShell either. JShell Functionality The JShell API will provide all of JShell's evaluation functionality. The code