{"id":2274,"date":"2020-02-21T01:12:15","date_gmt":"2020-02-21T01:12:15","guid":{"rendered":"http:\/\/kusuaks7\/?p=1879"},"modified":"2024-01-04T15:09:43","modified_gmt":"2024-01-04T15:09:43","slug":"whats-new-in-java-14","status":"publish","type":"post","link":"https:\/\/www.experfy.com\/blog\/software-ux-ui\/whats-new-in-java-14\/","title":{"rendered":"What\u2019s New in Java 14?"},"content":{"rendered":"\t\t
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Java 14 is going to be released on March 17, 2020. Besides ~2,400 bug fixes and small enhancements, the new version of Java contains 16 major enhancements, also called JEPs (Java Enhancement Proposals).<\/p>\n

Let\u2019s take a closer look at the major updates in Java 14: new switch expressions, better\u00a0NullPointerException<\/code>s, improvements in garbage collection, JFR event streaming, and more.<\/p>\n\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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Switch Expressions<\/h1>\n<\/h1>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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This update to the Java language was already available in Java 12 and 13 but only as a preview language feature, which means it was not enabled by default. Finally, the new switch expressions are released in Java 14. Making a long story short, Java 14 introduces a new simplified form of a switch block with\u00a0case L -> ...<\/code>\u00a0labels. The new switch expressions may help to simplify code in some cases. Here are a couple of examples.<\/p>\n

Let\u2019s assume that we have an enum that describes weekdays. We can write the following code using the new switch expressions:<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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switch (day) {\ncase MONDAY\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -> System.out.println(“Aweful”);\ncase TUESDAY, WEDNESDAY\u00a0 -> System.out.println(“Okay”);\ncase THURSDAY\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -> System.out.println(“Good”);\ncase FRIDAY\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -> System.out.println(“Great”);\ncase SATURDAY, SUNDAY\u00a0\u00a0\u00a0 -> System.out.println(“Awesome”);\n}<\/span><\/div>\n

Here we just used a single expression for each\u00a0case<\/code>. Note that the\u00a0switch<\/code>\u00a0block doesn’t use any\u00a0break<\/code>\u00a0statement, which makes it much shorter. The next example shows how the new switch expressions can return a value:<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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int numLetters = switch (day) {\ncase MONDAY, FRIDAY, SUNDAY -> 6;\ncase TUESDAY\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -> 7;\ncase THURSDAY, SATURDAY\u00a0\u00a0\u00a0\u00a0 -> 8;\ncase WEDNESDAY\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 -> 9;\n};<\/span><\/div>\n

It\u2019s also possible to write multi-line blocks and return a value with a new keyword\u00a0yield<\/code>:<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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int result = switch (s) {\ncase “Foo” -> 1;\ncase “Bar” -> 2;\ndefault\u00a0\u00a0\u00a0 -> {\nSystem.out.println(“Neither Foo nor Bar, hmmm…”);\nyield 0;\n}\n};<\/span><\/div>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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There are several important things that you need to keep in mind when you use the new switch expressions. For example, the cases of new switch expressions have to be exhaustive. It means that, for all possible values, there has to be a matching switch label. Or, since\u00a0yield<\/code>\u00a0is now a keyword, a class with a name\u00a0yield<\/code>\u00a0now becomes illegal in Java 14.<\/p>\n

If you’d like to learn more about the new switch expressions, you’re welcome to read\u00a0JEP 361<\/a>. The authors provided quite a lot of useful info about the new switch expressions.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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Helpful NullPointerExceptions<\/h1><\/h1>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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The JVM throws a\u00a0NullPointerException<\/code>\u00a0(NPE) when code tries to dereference a null reference. All Java developers have seen them before. For example, the following code may result in an NPE:<\/p>\n\n

foo.bar = 10;<\/pre>\n
The NPE is going to look like the following:<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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Exception in thread “main” java.lang.NullPointerException\nat App.main(App.java:17)<\/span><\/div>\n
The exception message contains a filename and a line where the null dereference happened. For the\u00a0foo.bar = 10;<\/code>\u00a0statement, it’s not too difficult to figure out that the NPE was thrown because the\u00a0foo<\/code>\u00a0variable was null. Unfortunately, sometimes it\u2019s not clear what exactly causes an NPE. For example, if either\u00a0a<\/code>,\u00a0b<\/code>\u00a0or\u00a0c<\/code>\u00a0is null, then an NPE is going to be thrown:<\/p>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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a.b.c.d = 42;<\/pre>\n
However, no matter which field was null, the NPE is going to look the same. It doesn\u2019t give any clue which field was actually null.<\/p>\n
Here is another example. If one of the nested arrays is null, it results in an NPE:<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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a[i][j][k] = 99;<\/pre>\n
Again, no matter which array was null, the NPE is going to look the same.<\/p>\n
Java 14 addresses this problem and makes NPEs more friendly. Now the JVM can figure out which variable was null, and then it lets the user know about it in the exception message. For example, a null dereference in the line\u00a0foo.bar = 10;<\/code>\u00a0is going to result in the following NPE:<\/p>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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Exception in thread “main” java.lang.NullPointerException:\nCannot assign field “bar” because “foo” is null\nat App.main(App.java:17)<\/span><\/div>\n
A null dereference in the line\u00a0a.b.c.d = 41;<\/code>\u00a0is going to result in the following NPE if\u00a0a.b<\/code>\u00a0was null:<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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Exception in thread “main” java.lang.NullPointerException:\nCannot read field “c” because “a.b” is null\nat App.main(App.java:17)<\/span><\/div>\n
The new info in\u00a0NullPointerException<\/code>s may be very helpful in analyzing its root cause and can make the developer\u2019s life a bit easier. By the way, the improvement has been available in SAP\u2019s JVM since 2006. Unfortunately, it took 14 years to finally bring it into OpenJDK.<\/p>\n
If you\u2019re interested in the details, the authors of the\u00a0JEP 358<\/a>\u00a0provided a lot of info about the new feature.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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Packaging Tool (Incubator)<\/h1><\/h1>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t
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Currently, a Java application is usually distributed as a simple JAR file. However, it\u2019s not very convenient, especially for a user of the application. It would be much better if the Java application were an installable package like MSI on Windows or DMG on Mac. This would allow Java applications to be distributed, installed, and uninstalled in a way that is familiar to users.<\/p>\n
JEP 343<\/a>\u00a0introduces the\u00a0jpackage<\/code>\u00a0tool, which packages a Java application into a platform-specific package that includes all of the necessary dependencies. Here\u2019s a list of supported package formats:<\/p>\n\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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