Skip to main content

How to convert Enum to List of String in Java 8?

Problem

 How to convert Enum to List of String in Java 8?

 Solution 


Using the Java 8 Streams, its map and collect functions we can convert Enum to List of Strings


 Code 


 import java.util.List;
import java.util.stream.Collectors;
import java.util.stream.Stream;

public class EnumToStringList {

public enum Alpha { A,B,C,D; } 
public static void main(String[] args) {
List<String> strings = Stream.of(Alpha.values()).map( 
                                             Alpha::name).collect( Collectors.toList());
}
}


Comments

  1. What if I've a list of Alpha with only values 'A' and 'B'
    How would you convert this list to a list of string ?

    ReplyDelete

Post a Comment

Popular posts from this blog

Eclipse - Server Tomcat v8.5 Server at localhost failed to start.

When I try to launch the tomcat from Eclipse, I encountered the following error Server Tomcat v8.5 Server at localhost failed to start. Solution Step 1  Delete the .snap file located at the following location     eclipse workspace Path\ .metadata\.plugins\org.eclipse.core.resources Step 2 Delete the  tmp0  folder from the following path      eclipse workspace Path \.metadata\.plugins\org.eclipse.wst.server.core Step 3  Delete the server from servers list Step 4  Remove already added Tomcat Server      i)  Click on Define a new Server     ii)  Select Server Runtime Environments     iii) Select the Tomcat Server and remove it as follows Remove Selected Server Step 5 Make sure that correct version of Server is configured in Project Properties Step 6 Restart the Eclipse IDE.

hibernate-release-5.4.4.Final - Required Jars

Introduction Hibernate (Object Relational Mapping framework) is an implementation of Java Persistence API (JPA) specification.   Required Jars for Hibernate 5.4.4 Following Jars resided inside the required folder are the mandatory jars required for Hibernate 5.4.4 antlr-2.7.7.jar byte-buddy-1.9.11.jar classmate-1.3.4.jar dom4j-2.1.1.jar FastInfoset-1.2.15.jar hibernate-commons-annotations-5.1.0.Final.jar hibernate-core-5.4.4.Final.jar istack-commons-runtime-3.0.7.jar jandex-2.0.5.Final.jar javassist-3.24.0-GA.jar javax.activation-api-1.2.0.jar javax.persistence-api-2.2.jar jaxb-api-2.3.1.jar jaxb-runtime-2.3.1.jar jboss-logging-3.3.2.Final.jar jboss-transaction-api_1.2_spec-1.1.1.Final.jar stax-ex-1.8.jar txw2-2.3.1.jar Hibernate 5.4.4 release is compatible with  Java 8 or 11  JPA 2.2 References https://hibernate.org/orm/releases/5.4/

spark-submit java.lang.NoClassDefFoundError: scala/runtime/java8/JFunction1$mcII$sp

Exception  Exception in thread "main" java.lang.BootstrapMethodError: java.lang.NoClassDefFoundError: scala/runtime/java8/JFunction1$mcII$sp         at SparkPi$.main(SparkPi.scala:14)         at SparkPi.main(SparkPi.scala)         at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)         at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) Problem: It seems that you have compiled and generated your jar file with an upper version of the Scala compiler than the one spark is using. Solution Step 1 Run the following command from spark-installed-directory\bin spark-shell.cmd (or.sh) and note the Scala version, My Spark version was 2.4.3 and Scala version 2.11.12 Step 2 Change the scala version into your build.sbt to 2.11.12 (per your configuration). My build.sbt is name := "SparkPi Project" version := "1.0" scalaVersion := "2.11.12" val sparkVersion = "2.4.5&qu