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Difference between revisions of "Java11/Examples"
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+ | ! colspan="3" | Basic Necessity : Compilation and Error Reporting | ||
+ | |- | ||
+ | ! scope="row" | Positive Compilation | ||
+ | | Use the following code: | ||
+ | <source lang="java"> | ||
+ | package pack1; | ||
+ | public class VarLambda { | ||
+ | |||
+ | public static void main(String[] args) { | ||
+ | I lam = (var x) -> { // var compiles here | ||
+ | System.out.println(x); | ||
+ | }; | ||
+ | lam.apply(20); | ||
+ | } | ||
+ | } | ||
+ | |||
+ | interface I { | ||
+ | public void apply(Integer k); | ||
+ | } | ||
+ | </source> | ||
+ | |||
+ | <br> | ||
+ | <br> | ||
+ | [[File:var11.compile.jpg]] | ||
+ | | Code compiles | ||
+ | |- | ||
+ | ! scope="row" | Compiler Error Case 1 | ||
+ | | | ||
+ | <source lang="java"> | ||
+ | package pack1; | ||
+ | public class VarLambdaErr { | ||
+ | |||
+ | public static void main(String[] args) { | ||
+ | I lam = (var x, z) -> { // should not mix with type-elided params | ||
+ | System.out.println(x); | ||
+ | }; | ||
+ | lam.apply(20); | ||
+ | } | ||
+ | } | ||
+ | |||
+ | interface I { | ||
+ | public void apply(Integer k, Integer z); | ||
+ | } | ||
+ | </source> | ||
+ | | Compiler errors are shown | ||
+ | |- | ||
+ | ! scope="row" | Compiler Error Case 2 | ||
+ | | | ||
+ | <source lang="java"> | ||
+ | package pack1; | ||
+ | public class VarLambdaErr { | ||
+ | |||
+ | public static void main(String[] args) { | ||
+ | I lam = (var x, Integer z) -> { // should not mix with non-var params | ||
+ | System.out.println(x); | ||
+ | }; | ||
+ | lam.apply(20, 200); | ||
+ | } | ||
+ | } | ||
+ | |||
+ | interface I { | ||
+ | public void apply(Integer k, Integer z); | ||
+ | } | ||
+ | </source> | ||
+ | | | ||
+ | Compiler errors shown | ||
+ | |- | ||
+ | ! colspan="3" | Hover and Navigation | ||
+ | |- | ||
+ | ! scope="row" | Hover | ||
+ | | Use the following code: | ||
+ | <source lang="java"> | ||
+ | package pack1; | ||
+ | public class VarLambda { | ||
+ | |||
+ | public static void main(String[] args) { | ||
+ | I lam = (var x) -> { // hover over var | ||
+ | System.out.println(x); | ||
+ | }; | ||
+ | lam.apply(20); | ||
+ | } | ||
+ | } | ||
+ | |||
+ | interface I { | ||
+ | public void apply(Integer k); | ||
+ | } | ||
+ | </source> | ||
+ | |||
+ | <br> | ||
+ | <br> | ||
+ | [[File:var11.hover.jpg]] | ||
+ | | Hover and Navigation | ||
+ | |- | ||
+ | ! colspan="3" | Nestmates | ||
+ | |- | ||
+ | ! scope="row" | Basic Nesting Principles | ||
+ | | | ||
+ | <b>Description: Nest Based Access - A JVM Concept.</b> | ||
+ | A top level class and all inner classes form a single unit for access, a "nest".JVM | ||
+ | specification added two attributes in the classfile NestHost and NestMember. The top | ||
+ | most class will have the NestMember attribute listing all the members while each of | ||
+ | the inner classes will have a NestHost attribute listing the top level class. Using | ||
+ | this, some of the synthetic bridge methods are elided transparent to the programmer. | ||
+ | Note that this feature is relevant only for tools that process byte code and hence, | ||
+ | in general, this feature would be "transparent" to a "normal" programmer. This feature | ||
+ | is applicable for byte code processors, for eg our Disassembler has been enhanced to | ||
+ | show these attributes. For further info please read JEP 181. | ||
+ | <br> | ||
+ | <source lang="java"> | ||
+ | public class X { | ||
+ | private class A { | ||
+ | class B {} | ||
+ | } | ||
+ | private class Y extends A { | ||
+ | } | ||
+ | } | ||
+ | </source> | ||
+ | <br> | ||
+ | | In X.class (Disassembled) | ||
+ | Nest Members: | ||
+ | #21 X$A, | ||
+ | #24 X$A$B, | ||
+ | #27 X$Y | ||
+ | |||
+ | In each of X$A, X$A$B, X$Y the attribute: | ||
+ | Nest Host: #22 X |
Latest revision as of 02:43, 13 March 2019
This is an informal page listing examples of features that are implemented by the Java 11 Support. You are welcome to try out these examples. If you find bugs, please file a bug after checking for a duplicate entry here.