Shulou(Shulou.com)06/03 Report--

Today, I will talk to you about how to use jShell to quickly achieve code prototyping, many people may not know much about it. In order to make you understand better, the editor summarizes the following contents. I hope you can get something according to this article.

Interpretive programming languages have been able to execute code quickly on the command line many years ago. You don't need to start IDE or compile, and you can type in the code to see the results immediately. This approach has proved to be very helpful to beginners. Because you try a new programming language like this, you won't be bothered by compilers, dependencies, and build systems. JShell is an often overlooked feature in JDK9: it is a Read-Evaluate-PrintLoop (REPL) environment where Java code can be called without compilation in JSHell.

What is REPL?

In short, just type a few commands (Read), it will be interpreted (Evalueate), and the result of the command will be forwarded (Print). This process continues until Loop. This is R (ead) E (valuate) P (rint) L (oop).

Start JShell

If the command line supports JavaJDK9 or later, simply type jshell to start JShell.

Call JShell

When the jshell > prompt appears, it indicates that JShell is currently in R (ead) mode, waiting for input.

To quickly browse the available commands, type / help

JShellhelp

Commands, code completion, and references

JShell uses the TAB key for code hints and automatic completion. Enter System.out, press TAB to complete the System.out.println ("HelloWorld"):

Code hints and automatic completion

In fact, REPL prints all the commands entered, so there is no need for System.out print commands

Variable and result reference

One of the interesting features of JShell is its support for forward references. Forward references refer to methods, variables, or classes that are not defined in JShell. For example, there is a valueOfStocks method that calculates the total value of stocks held based on the current price and the number of stocks you own. You can define the method of calculation before providing the actual quantity and current price of each stock.

Use external development libraries

JShell supports saving and importing resources (that is, JShell scripts) locally, using the / save and / open commands, respectively. You can also load previously saved sessions when JShell starts.

With JShell, you can easily test code snippets or prototype algorithms without compiling code. In the REPL environment, the commands entered can be fed back directly. For more information about JShell, you can refer to Oracle's JShell tutorial.

After reading the above, do you have any further understanding of how to use jShell to quickly implement code prototyping? If you want to know more knowledge or related content, please follow the industry information channel, thank you for your support.

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