Techie Shah

Problem When I tried to add JDK 14 to my eclipse, the following error was shown Target is not a JDK root. System library was not found. Target is not a JDK root. System library was not found. My downloaded JDK folder was named as jdk-14 Solution I simply renamed my folder from jdk-14 to jdk-14.0 and it worked. The jdk 14 was successfully added to the Eclipse. Conclusion I t seems that sometimes Eclipse is not able to locate the jdk folder, renaming the folder refreshes the cache of Eclipse and then respective folder is located by Eclipse.

Problem If you try to print the following XML on the HTML page, it will not be visible <website> <name>techieshah.com</name> <url>http://techieshah.com</url> </website> Solution Replace less than sign i.e. <   with  &lt; Replace greater than sign i.e. > with  &gt;

Introduction In this post, we will learn how to print Hibernate Query parameters using log4j. Requirments log4j-api-2.13.1.jar log4j-core-2.13.1.jar Step 1 Place the above two log4j jars inside the lib directory. For web applications, the lib directory is located inside the WEB-INF folder. Step 2 Create a file by the name of  log4j2.xml and place it inside your src folder. Step 3 Place the following XML code inside the  log4j2.xml file <configuration status="WARN"> <appenders> <console name="LogToConsole" target="SYSTEM_OUT"> <patternlayout pattern="%d{HH:mm:ss.SSS} [%t] %-5level %logger{36} - %msg%n"> </patternlayout></console> </appenders> <loggers> <logger additivity="false" level="debug" name="org.myapp"> <appenderref ref="LogToConsole"> &

Exception Uncaught ReferenceError: $ is not defined     at timer.js:14 Solution  Please make sure that JQuery JS file is added in the HTML file  JQuery JS file should be declared first than other JS files like <script src='https://code.jquery.com/jquery-3.4.1.min.js'></script>      <script src='js/app.min.js'></script> <script src='js/timer.js'></script>

Introduction In this post, we will explore how to convert an array of bytes i.e. byte[] to String in Java. For this functionality, we will use the following constructor of java.lang.String class String (byte[] bytes,  String  enc) Example import java.nio.charset.StandardCharsets; public class ByteArrayToString { public static void main(String[] args) { byte[] bytes = "a quick fox jumps over the lazy dog".getBytes(); // convert the bytes to String System.out.println("bytes = " + bytes); System.out.println( "bytes.toString() = " + bytes.toString()); String myString = new String ( bytes , StandardCharsets.UTF_8); System.out.println("myString = " + myString); } } Output bytes = [B@41a4555e bytes.toString() = [B@41a4555e myString = a quick fox jumps over the lazy dog Conclusion In this post, we learned how to convert an array of bytes to String.

Introduction In this post, we will learn how to convert String to InputStream in Java. Example import java.io.ByteArrayInputStream; import java.io.InputStream; public class StringToInputStream { public static void main(String[] args) { String text = "A quick fox jumps over a lazy dog"; try ( InputStream inputStream = convertToInputStream(text) ) { //TODO you business logic goes here } catch (Exception e) { e.printStackTrace(); } } private static InputStream convertToInputStream(String text) throws Exception { return new ByteArrayInputStream(text.getBytes()); } } Conclusion This is the simplest and shortest way to convert a String to InputStream in Java.

Introduction Mostly we make a connection to Oracle using JDBC through SID. Recently I have to make a connection to Oracle using Service Name. I am writing this post to share my experience. SID Connection String  jdbc:oracle:thin:@IP:1521:SID Service Name connection String  jdbc:oracle:thin:@(description=(address=(host=IP)(protocol=tcp)(port=1521))(connect_data=(service_name=UR_SERVICE_NAME))) Replace Service Name and host address per your configuration These strings work both for plain JDBC and hibernate. For hibernate configuration, put the above string inside <property name="connection.url">Above connection String</property> tag of hibernate.cfg.xml. Conclusion In this post, we learn how to connect to Oracle using both SID and Service Name. Happy learning

Introduction In this tutorial, we will learn how to convert InputStream to String in Java. Example import java.io.InputStream; import java.net.URL; public class InputStreamToString { public static void main(String[] args) { //very frequent asked question in interview , regarding closable interface try(InputStream inputStream = new URL("https://www.oracle.com/index.html").openStream()){ System.out.println(convertToString(inputStream)); }catch (Exception e) { // TODO: handle exception } } private static String convertToString(InputStream inputStream) throws Exception{ return new String(inputStream.readAllBytes()); } } Conclusion Above example is the simplest method to convert an Inpustream to String in Java. There are alternate solutions available like using commonio jar and converting InputStream to ByteStream etc. Hope you enjoy this tutorial. Happy learning 

Introduction In this tutorial, we will learn how to skip or display % in a String using String.format MyStringFormatter .java  public class MyStringFormatter { public static void main(String[] args) { System.out.println(String.format( "Your score is %d % " ,65) ); } } Output Exception in thread "main" java.util.UnknownFormatConversionException: Conversion = ' ' at java.base/java.util.Formatter.checkText(Formatter.java:2732) at java.base/java.util.Formatter.parse(Formatter.java:2718) at java.base/java.util.Formatter.format(Formatter.java:2655) at java.base/java.util.Formatter.format(Formatter.java:2609) at java.base/java.lang.String.format(String.java:2897) at MyStringFormatter.main(MyStringFormatter.java:4) Solution To display a % in String when using String.format , you have to escape a % with % i.e. %% public class MyStringFormatter { public static void main(String[] args) { System.out.println(String.fo

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