How to Fix Unsupported major.minor version 60.0, 59.0, 58.0, 57.0, 56.0, 55.0, 54, 0, 53.0, 52.00, 51.0 Error in Eclipse & Java

The UnsupportedClassVersionError is a big nightmare for Java developers, probably the next biggest after NoClassDefFoundError and ClassNotFoundException but it's slightly easier to solve. The root cause of this error is that your code is compiled using a higher JDK version and you are trying to run it on the lower version. For example, the Unsupported major.minor version 53.0 means your code is compiled in JDK 9 (the class version 52 corresponds to JDK 9) and you are trying to run it on any JRE lower than Java 9, probably JDK 8, 7, or 6.

How to fix java.lang.OutOfMemoryError: unable to create new native thread [Solution]

There are several types of OutOfMemoryError in Java e.g. OutOfMemoryError related to Java heap space and permgen space, and a new one coming in Java 8, Java.lang.OutOfMemoryError: Metaspace. Each and every OutOfMemoryError has its own unique reason and corresponding unique solution. For example, java.langOutOfMemoryError: Java Heap Space comes when the application has exhausted all heap memory and tries to create an object which requires further memory allocation, At that time JVM throws this error to tell the application that it's not possible to create an object.

How to solve java.lang.NoClassDefFoundError: org/springframework/beans/factory/SmartInitializingSingleton in Spring Boot [Solved]

Problem:
I was trying to run a HelloWorld program using Spring Boot when I got this error:

Exception in thread "main" java.lang.IllegalStateException: Could not evaluate condition on org.springframework.boot.autoconfigure.PropertyPlaceholderAutoConfiguration#propertySourcesPlaceholderConfigurer due to internal class not found. This can happen if you are @ComponentScanning a springframework package (e.g. if you put a @ComponentScan in the default package by mistake)
at org.springframework.boot.autoconfigure.condition.SpringBootCondition.matches(SpringBootCondition.java:52)
at org.springframework.context.annotation.ConditionEvaluator.shouldSkip(ConditionEvaluator.java:92)
at org.springframework.context.annotation.ConfigurationClassBeanDefinitionReader.loadBeanDefinitionsForBeanMethod(ConfigurationClassBeanDefinitionReader.java:174)
at org.springframework.context.annotation.ConfigurationClassBeanDefinitionReader.loadBeanDefinitionsForConfigurationClass(ConfigurationClassBeanDefinitionReader.java:136)

5 Tips to Fix Exception in thread "main" java.lang.NoClassDefFoundError in Java, Examples

NoClassDefFoundError in Java
The Exception in thread "main" java.lang.NoClassDefFoundError is a common error in Java that occurs if a ClassLoader cannot find a particular class in the classpath while trying to load it. The Exception in thread "main" suggests that this error has occurred in the main thread, the thread which is responsible for running the Java application. This error can occur to any thread, but if it happens in the main thread, then your program will crash because Java program runs only until main() thread is running or any other non-daemon thread is running. As per Javadoc, NoClassDefFoundError can be thrown during the linking or loading of the class file. 

java.lang.IllegalStateException: getOutputStream() has already been called for this response

This error comes when you call to include() or forward() method after calling the getOutputStream() from ServletResponse object and writing into it.  This error is similar to java.lang.IllegalStateException: getWriter() has already been called for this response error, which we have seen in the earlier article.

This is the exception:
org.apache.jasper.JasperException: java.lang.IllegalStateException: getOutputStream() has already been called for this response
org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:502)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:424)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:313)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:260)
javax.servlet.http.HttpServlet.service(HttpServlet.java:723)
HelloServlet.doGet(HelloServlet.java:25)
javax.servlet.http.HttpServlet.service(HttpServlet.java:617)
javax.servlet.http.HttpServlet.service(HttpServlet.java:723)

and here is the root cause :

How to fix java.lang.IllegalStateException: getWriter() has already been called for this response [Solution]

This error comes when a Servlet calls the getOutputStream() method on the response object for writing something after calling the include() method. Suppose a Servlet calls the include() method to load the response of a JSP. Since JSP has already written the response on it hence again opening OutputStream on the response object is illegal, you get the java.lang.IllegalStateException: getWriter() has already been called for this response error. This error also comes when you try to include the response of another Servlet and then tries to write something on the output stream again. In short, your Servlet should never write anything on the response object after calling the include() method. 

How to fix java.lang.ClassNotFoundException: org.apache.commons.logging.LogFactory

Problem: You are getting java.lang.ClassNotFoundException: org.apache.commons.logging.LogFactory in your Java program, which uses a logging framework to log messages into a log file.  It could be direct dependency or indirect dependency due to any framework e.g. Spring, Hibernate, or any open-source library like jackson or any other JSON parsing library.

How to create User Defined Exception class in Java? Example Tutorial

Java has very good support for handling Errors and Exceptions, It has a well-defined Exception hierarchy and language level support to throw and catch Exceptions and deal with them. Java Programmers often deal with built-in exceptions from java.lang package and several others which are already defined in JDK API like NullPointerException. If you have read Effective Java, you may remember the advice of Joshua Bloch regarding Exception. According to him, you should try to reuse the Exception classes provided in the JDK, like IndexOutOfBoundException, ArithmeticException, IOException, and java.lang.ArrayIndexOutOfBoundsException , instead of creating new ones for a similar purpose.

Difference between NoClassDefFoundError vs ClassNotFoundExcepiton in Java

Both NoClassDefFoundError and ClassNotFoundException are dangerous errors that come when JVM or ClassLoader not able to locate class during the class loading process. Since different ClassLoader loads classes from a different location, sometimes this issue may be caused because of incorrect CLASSPATH as well i.e. some JAR files from lib are missing or from the old version. Though looks quite similar there is a subtle difference between NoClassDefFoundError and ClassNotFoundException, NoClassDefFoundError indicates that the class was present during the time of compilation but not available when you run Java program, sometimes error on static initializer block can also result in NoClassDefFoundError.

How to Fix java.lang.OutOfMemoryError: Metaspace in Java? [Solution]

Hello guys, An OutOfMemoryError related to Metaspace indicates that your Java application has exhausted the memory allocated for the Metaspace area, which is used for class metadata and method information. This error typically occurs when an application dynamically generates and loads a large number of classes or when the Metaspace size is not properly configured to handle the application's requirements.  Java class metadata (the virtual machine's internal presentation of Java class) is allocated in native memory (referred to here as metaspace). If metaspace for class metadata is exhausted, a java.lang.OutOfMemoryError exception with a detail MetaSpace is thrown. 

How to fix java module error "Caused by: java.lang.reflect.InaccessibleObjectException: module java.base does not "opens java.util" to unnamed module"

The error message you're seeing, (Caused by: java.lang.reflect.InaccessibleObjectException: Unable to make field private final java.util.Comparator java.util.TreeMap.comparator accessible: module java.base does not "opens java.util" to unnamed module @6d4a82") or  java.lang.reflect.InaccessibleObjectException, is related to module system changes introduced in Java 9 and later versions. It occurs when you try to access a field, method, or class that is not accessible due to module restrictions. In this case, it appears that you're trying to access the private final java.util.Comparator field of a java.util.TreeMap, which is not accessible because the java.base module does not open java.util to unnamed modules.

Top 25 Java Error and Exception Interview Questions Answers

1) The difference between checked and Unchecked Exceptions in Java?
For checked exceptions, the compiler ensures that they are either handled using try-catch, try-finally, or try-catch-finally block or thrown away. If a method, which throws a checked exception like IOException, and doesn't handle them or doesn't declare them in the throws class of the method, a compile-time error will occur. On the other hand, the compiler doesn't do similar checks for an unchecked exception, that's why it is known as un-checked. These are also called runtime exceptions because they extend java.lang.RuntimeException.

How to Solve "Error starting Application Context" in Spring Framework?

 Hello guys, Spring Boot is a popular framework for building Java applications, providing a streamlined development experience. However, like any software, Spring Boot applications can encounter errors during startup. One common error that developers may encounter is the "Error starting ApplicationContext" error. This error typically indicates an issue with the application's configuration or dependencies but it's really hard to find what exactly is wrong and how to fix it. In the past, I have shared tips on how to fix error creating bean error and In this article, we will explore various solutions to fix this error and ensure a successful startup of your Spring Boot application.

How to Handle REST exception in Spring Boot Application? Example Tutorial

Hello everyone, in this article we are going to take a look at how to handle REST API exceptions in Spring Boot. It is crucial to handle errors correctly in APIs by displaying meaningful messages as it helps API clients to address problems easily. What happens if we don’t handle the errors manually? By default, the spring application throws a stack trace, which is difficult to understand. Stack traces are mainly for developers hence it is useless for API clients. That's why its very important to use proper HTTP code and error messages to convey errors and exception to client and also logging so that support team can better handle them. Ideally you should tell what went wrong and how to fix it? For example, if the error is due to duplicate data then clearly say, already existed, try with a new one. Similarly, if authentication fail then clearly say authentication failed instead of throwing some other exception. 

What is try with resource in Java? Example tutorial

In Java we normally use resources like file, network connection, socket connection, database connection etc ,dealing with resources is not a difficult task but what if after using the resources programmers forget to close the resources. As we know in Java everything is Object so if we forget to close or shut down the resource its responsibility of GC that will recollect it when its no longer used but we can reduce resource exhaustion by explicitly closing the resources as soon we done with our job with the resources. Some resources like database connection are very precious and would surely run out of resources if waited for finalization. Many database servers only accept a certain number of connections so if forget to close properly will create problem.

How to Fix java.lang.VerifyError: Expecting a stack map frame at branch target 14 in method at offset JDK 7 [Solved]

Hello guys, today, we'll take a look at the not-so-common error for Java applications. If you have been working in Java for a couple of years then you might have seen this dreaded "java.lang.VerifyError: Expecting a stack map frame at branch target 14 in method at offset JDK 7" error in your application log or in Eclipse, particularly if you are running your Java application in Java 7. The main cause of this error, "java.lang.VerifyError: Expecting a stack map frame at branch target ... in the method ... at offset 0 error comes when you have some library, JAR file which is only compatible with Java 1.6 or below and you are running your program in JDK 1.7.

When to throw and catch Exception in Java? [Best Practice]

Exceptions are one of the confusing and misunderstood topics in Java, but at the same time, too big to ignore. In fact, good knowledge of Errors and Exception handling practices is one criterion, which differentiates a good Java developer from an average one. So what is confusing about Exception in Java? Well, many things like When to throw Exception or When to catch Exception, When to use checked exception or unchecked exception, should we catch errors like java.lang.OutOfMemoryError? Shall I use an error code instead of an Exception and a lot more? Well, I cannot answer all these questions in one post, so I will pick the first one when to catch or throw any Exception in Java.

How to Fix java.sql.BatchUpdateException: Error converting data type float to numeric - Java + SQL Server

This error can come if you are inserting or updating a NUMERIC column in the Microsoft SQL Server database from a Java Program using the executeUpdate()method, I mean executing a  batch update query. It could also happen if you are calling a stored procedure and passing a float value corresponding to a NUMERIC column, and the value happened to be out-of-range like generating "Arithmetic overflow error converting numeric to data type numeric" on the SQL Server end. For example, if your column is defined as NUMERIC (6,2) the maximum value it can represent is 9999.99, not 999999.99. 

How to Fix SQLServerException: The index is out of range? JDBC Example

I was executing a stored procedure against SQL SERVER 2008 database from Java program using CallableStatement, but unfortunately, I was getting the following error "SQLServerException: The index 58 is out of range". Since I am passing a lot of parameters I thought that something is wrong with a number of parameters I was passing to the stored proc. My stored procedure had 58 INPUT parameters, as soon as I removed the 58th INPUT parameter the error goes away, which confirmed my belief that SQL Server supports a maximum of 57 INPUT parameters in stored procedure via JDBC. 

How to deal with java.lang.NullPointerExceptionin Java? Cause, Solution, and Tips to avoid NPE

Hello Java programmers, if you want to learn what is NullPointerExcpeiton in Java and how to deal with NullPointerException or NPE then you have come to the right place. NullPointerException in Java is an unchecked Exception defined in java.lang package and comes when a member of an object either field or method is called on an object which is null. null is a keyword in Java that means nothing and the calling method on an object whose value is null will result in NullPointerException. Since the default value of Object is null, if you call any method or access any field on an Object which is not initialized will throw NullPointerException.