--- title: "Java 16: An Introduction from a Java 8 Monogamist" description: "With the recent release of Java 16, we thought it would be nice to provide a\nquick overview of its new features and upgrades. While the update introduces a\nnumber of behind-the-scenes changes, this post will focus instead on coding\nfeatures that are more immediately relevant to programmers in their" image: https://blog.ippon.tech/hubfs/Imported_Blog_Media/Java-16-_-An-Introduction-from-a-Java-8-Monogamist-3.png --- [Skip to main content](https://blog.ippon.tech/java-16-introduction#main) [![IpponLogoKleinBlue](https://blog.ippon.tech/hs-fs/hubfs/IpponLogoKleinBlue.png?width=219&height=64&name=IpponLogoKleinBlue.png) ![IpponLogoKleinBlue](https://blog.ippon.tech/hs-fs/hubfs/IpponLogoKleinBlue.png?width=219&height=64&name=IpponLogoKleinBlue.png) ![IpponLogoKleinBlue](https://blog.ippon.tech/hs-fs/hubfs/IpponLogoKleinBlue.png?width=168&height=49&name=IpponLogoKleinBlue.png) ![IpponLogoKleinBlue](https://blog.ippon.tech/hs-fs/hubfs/IpponLogoKleinBlue.png?width=168&height=49&name=IpponLogoKleinBlue.png)](https://ipponusa.com/) - [Home](https://ipponusa.com) - [Show submenu for About About](https://ipponusa.com/about-us) - [Who We Are](https://ipponusa.com/who-we-are) - [Careers](https://ipponusa.com/careers) - [Show submenu for Our Partners Our Partners](https://ipponusa.com/our-partners/) - [AWS](https://ipponusa.com/our-partners/aws/) - [Snowflake](https://ipponusa.com/our-partners/snowflake/) - [Databricks](https://ipponusa.com/our-partners/databricks/) - [Microsoft](https://ipponusa.com/our-partners/microsoft/) - [Show submenu for Services Services](https://ipponusa.com/services) - [Snowflake](https://ipponusa.com/service/snowflake-concierge/) - [Artificial Intelligence](https://ipponusa.com/service/artificial-intelligence/) - [Data & Analytics](https://ipponusa.com/service/data-analytics/) - [Cloud Strategy](https://ipponusa.com/service/cloud-strategy/) - [Platform Modernization](https://ipponusa.com/service/platform-moderization/) - [Product Innovation](https://ipponusa.com/service/product-innovation/) - [Operating Model](https://ipponusa.com/service/operating-model/) - [Blogs](https://blog.ippon.tech/) - [Success Stories](https://ipponusa.com/success-stories/) - [Show submenu for Resources Resources](https://ipponusa.com/resources/) - [eBooks](https://ipponusa.com/ebooks/) - [The Data Pour](https://info.ippon.tech/the-data-pour) - [Videos & Webinars](https://info.ippon.tech/videos-and-webinars) - [Media Center](https://ipponusa.com/media-center/) Search Open main navigation Close main navigation - [Home](https://ipponusa.com) - Show submenu for About About - About - [About](https://ipponusa.com/about-us) - [Who We Are](https://ipponusa.com/who-we-are) - [Careers](https://ipponusa.com/careers) - Show submenu for Our Partners Our Partners - Our Partners - [Our Partners](https://ipponusa.com/our-partners/) - [AWS](https://ipponusa.com/our-partners/aws/) - [Snowflake](https://ipponusa.com/our-partners/snowflake/) - [Databricks](https://ipponusa.com/our-partners/databricks/) - [Microsoft](https://ipponusa.com/our-partners/microsoft/) - Show submenu for Services Services - Services - [Services](https://ipponusa.com/services) - [Snowflake](https://ipponusa.com/service/snowflake-concierge/) - [Artificial Intelligence](https://ipponusa.com/service/artificial-intelligence/) - [Data & Analytics](https://ipponusa.com/service/data-analytics/) - [Cloud Strategy](https://ipponusa.com/service/cloud-strategy/) - [Platform Modernization](https://ipponusa.com/service/platform-moderization/) - [Product Innovation](https://ipponusa.com/service/product-innovation/) - [Operating Model](https://ipponusa.com/service/operating-model/) - [Blogs](https://blog.ippon.tech/) - [Success Stories](https://ipponusa.com/success-stories/) - Show submenu for Resources Resources - Resources - [Resources](https://ipponusa.com/resources/) - [eBooks](https://ipponusa.com/ebooks/) - [The Data Pour](https://info.ippon.tech/the-data-pour) - [Videos & Webinars](https://info.ippon.tech/videos-and-webinars) - [Media Center](https://ipponusa.com/media-center/) - Search - [Contact Us](https://ipponusa.com/contact/) [Contact Us](https://ipponusa.com/contact/) # Java 16: An Introduction from a Java 8 Monogamist ![Mike Mitchell](https://app.hubspot.com/settings/avatar/d41d8cd98f00b204e9800998ecf8427e) by [Mike Mitchell](https://blog.ippon.tech/author/mike-mitchell) March 26, 2021 ![Java 16: An Introduction from a Java 8 Monogamist](https://blog.ippon.tech/hubfs/Imported_Blog_Media/Java-16-_-An-Introduction-from-a-Java-8-Monogamist-3.png) [Java](https://blog.ippon.tech/tag/java/) [Ippon](https://blog.ippon.tech/tag/ippon/) [introduction](https://blog.ippon.tech/tag/introduction/) [new features](https://blog.ippon.tech/tag/new-features/) [beginner](https://blog.ippon.tech/tag/beginner/) [intro](https://blog.ippon.tech/tag/intro/) [oracle](https://blog.ippon.tech/tag/oracle/) [java 16](https://blog.ippon.tech/tag/java-16/)   With the recent release of Java 16, we thought it would be nice to provide a quick overview of its new features and upgrades. While the update introduces a number of behind-the-scenes changes, this post will focus instead on coding features that are more immediately relevant to programmers in their daily work. Before diving in, let's take a look at the coding upgrades made between Java 9 and Java 15.   ## Java 9 and 10 ***JShell***: execute and experiment with Java code without creating a class or main method; those of you familiar with the Python shell will quickly be able to put this to good use ``` jdk-9\bin>jshell.exe | Welcome to JShell -- Version 9 | For an introduction type: /help intro jshell> "This is my long string. I want a part of it".substring(8,19); $5 ==> "my long string" ``` ***.copyOf()***: create an unmodifiable copy of lists, maps, and sets (modify throws exception) ``` List copyList = List.copyOf(someIntList); copyList.add(4); //throws exception ``` ***.toUnmodifable()***: similar to *copyOf*(), but for stream collection ``` List evenList = someIntList.stream() .filter(i -> i % 2 == 0) .collect(Collectors.toUnmodifiableList()); evenList.add(4); //throws exception ``` ***.orElseThrow()***: if no value is present for an optional, throw a specified exception ``` Integer firstEven = someIntList.stream() .filter(i -> i % 2 == 0) .findFirst() .orElseThrow(); ``` ***var***: new reserved type name, similar to its use in Scala; allows for type inference; must be initialized, and cannot be initialized to null (needed for compiler to determine what to do); only supported for local in-method variables ``` Map map = new HashMap<>(); //vs var idToNameMap = new HashMap(); var message = "Hello, Java 10"; assertTrue(message instance of String); ``` ## Java 11 **New helpful String methods:** .*isBlank*() .*lines*() .*strip*() .*stripLeading*() .*stripTrailing*() ``` String multilineString = "I love \n \n Java 11 \n a lot."; List lines = multilineString.lines() .filter(line -> !line.isBlank()) .map(String::strip) .collect(Collectors.toList()); assertThat(lines).containsExactly("I love", "Java 11", "a lot."); ``` ***.toArray()***: simpler collection conversion to an array. Why is this useful? Arrays are of a fixed size, have better performance (although cost more memory), and can hold either objects or primitives ``` List sampleList = Arrays.asList("Java", "Kotlin"); String[] sampleArray = sampleList.toArray(String[]::new); assertThat(sampleArray).containsExactly("Java", "Kotlin"); ``` ***var now supported for lambda parameters***: more readable than explicit type definition; allows for type annotations within streams ``` List sampleList = Arrays.asList("Java", "Kotlin"); String resultString = sampleList.stream() .map((@Nonnull var x) -> x.toUpperCase()) .collect(Collectors.joining(", ")); assertThat(resultString).isEqualTo("JAVA, KOTLIN"); ``` ***Directly run java without javac compiling***: allows for single file source code, without the need for pre-compilation ``` $ javac HelloWorld.java $ java HelloWorld Hello Java 8! //vs $ java HelloWorld.java Hello Java 11! ``` ## Java 12 **New String methods:** String *.indent()* and *.transform()* ``` String text = "Hello Ippon!\nThis is a Java 12 blog post."; text = text.indent(4); System.out.println(text); //prints this (with an indent of 4 spaces) Hello Ippon! This is a Java 12 blog post. ``` ``` String text = "Hello Ippon!\nThis is a Java 12 blog post."; text = text.indent(-10); System.out.println(text); //prints this (with no indent) Hello Ippon! This is a Java 12 blog post. ``` ``` String text = "Ippon"; String transformed = text.transform(value -> new StringBuilder(value).reverse().toString() assertEquals("noppI", transformed); ``` **Files package .*mismatch()* static method**: will return -1 if two files are matching, or the index of the first differentiating byte; no more byte array comparisons! ``` Path filePath1 = Files.createTempFile("file1", ".txt"); Path filePath2 = Files.createTempFile("file2", ".txt"); Files.writeString(filePath1, "Java 12 Article"); Files.writeString(filePath2, "Java 12 Article"); long mismatch = Files.mismatch(filePath1, filePath2); assertEquals(-1, mismatch); ``` ***CompactNumberFormat***: convert numbers to strings based on patterns provided by a given locale ``` NumberFormat shortFormat = NumberFormat.getCompactNumberInstance(new Locale("en", "US"), NumberFormat.Style.SHORT); shortFormat.setMaximumFractionDigits(2); assertEquals("2.59K", shortFormat.format(2592)); NumberFormat longFormat = NumberFormat.getCompactNumberInstance(new Locale("en", "US"), NumberFormat.Style.LONG); longFormat.setMaximumFractionDigits(2); assertEquals("2.59 thousand", longFormat.format(2592)); ``` ## Java 13 and 14 **Improved switch expression concision**: we can now define multiple cases within a single line, without the need for breaks ``` boolean isTodayHoliday; switch (day) { case "MONDAY": case "TUESDAY": case "WEDNESDAY": case "THURSDAY": case "FRIDAY": isTodayHoliday = false; break; case "SATURDAY": case "SUNDAY": isTodayHoliday = true; break; default: throw new IllegalArgumentException("What's a " + day); } //vs boolean isTodayHoliday = switch (day) { case "MONDAY", "TUESDAY", "WEDNESDAY", "THURSDAY", "FRIDAY" -> false; case "SATURDAY", "SUNDAY" -> true; default -> throw new IllegalArgumentException("What's a " + day); }; ``` More helpful and descriptive Null Pointer Exceptions. I can already hear you quietly saying to yourself, "Finally!" ``` int[] arr = null; arr[0] = 1; Exception in thread "main" java.lang.NullPointerException at com.baeldung.MyClass.main(MyClass.java:27) //vs int[] arr = null; arr[0] = 1; java.lang.NullPointerException: Cannot store to int array because "a" is null ``` ## Java 15 **Text blocks:** Now fully supported as a production ready feature ``` String html = """

Hello World.

"""; ``` ``` String multiline = "A quick brown fox jumps over a lazy dog; the lazy dog howls loudly."; //vs String multiline = """ A quick brown fox jumps over a lazy dog; \ the lazy dog howls loudly."""; ``` **Sealed classes:** More control over and ability to be restrictive with inheritance; the below code will prevent any object other than Employee and Manager from ever extending Person ``` public abstract sealed class Person permits Employee, Manager { //... } public final class Employee extends Person {} public non-sealed class Manager extends Person {} //the below will not throw a warning, even without //a final 'else' condition, as the compiler can infer //from the sealed class definition that all possibilities //have been exhausted if (person instanceof Employee) { return ((Employee) person).getEmployeeId(); } else if (person instanceof Manager) { return ((Manager) person).getSupervisorId(); } ``` ## Java 16 **Records:** More concise definitions of immutable DTOs; compiler will also auto-provide *toString*, *equals*, and *hashCode* methods. (Note: while records were previewed in Java versions 14 and 15, Java 16 releases them as a production-ready feature) ``` //Immutable DTO Before public class Person { private final String name; private final int age; public Person(String name, int age) { this.name = name; this.age = age; } public String getName() { return name; } public int getAge() { return age; } } //vs Immutable DTO After public record Person(String name, int age) {} //and public record Person(String name, int age) { public Person { if(age < 0) { throw new IllegalArgumentException("Age cannot be negative"); } } } ``` **Pattern matching:** Remove boilerplate code required for *instanceof* checks; you can now have pattern matching and conditionals within the same line of code. (Note: similar to Records, this was previewed in earlier versions, but is now a fully supported production-ready feature) ``` if (person instanceof Employee) { Employee employee = (Employee) person; Date hireDate = employee.getHireDate(); //... } //vs if (person instanceof Employee employee) { Date hireDate = employee.getHireDate(); //... } //and if (person instanceof Employee employee && employee.getYearsOfService() > 5) { //... } ``` You probably noticed that these updates don't appear to include all that many changes. This is both because Java releases now occur every 6 months, and that they tend to include mostly under-the-hood upgrades. For a more in-depth look at the differences between Java's LTS and non-LTS releases, see: [https://blog.ippon.tech/comparing-java-lts-releases/](https://blog.ippon.tech/comparing-java-lts-releases/) We hope that this introduction will allow for you to more quickly dive into post-Java 8 versions and use what they have to offer in your daily work. For more information regarding non-coding-related changes made in these updates, be sure to check out Oracle's very helpful JDK release notes library. Thanks for reading! ### **Sources** Oracle Baeldung Ippon Blog Journal Dev Info World Educba Javat Point Plural Sight ## Related Articles ##### [![Introduction to Karate](https://blog.ippon.tech/hs-fs/hubfs/Imported_Blog_Media/karate-3961079_1280-3.jpg?width=520&height=294&name=karate-3961079_1280-3.jpg) cucumber • September 1, 2021 Introduction to Karate 6 min read](https://blog.ippon.tech/introduction-to-karate) ### Comments ### Subscribe to Our Blog! Stay informed with the latest insights and updates by signing up for our weekly blog newsletter – delivered straight to your inbox! 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