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java.lang.reflect.InvocationTargetException: null

Root problem Looks like bug https://hibernate.atlassian.net/browse/HHH-12368 They recommended set property (I believe it’s the best workaround): as workaround is to disable hibernate to detect this function by setting flag hibernate.jdbc.lob.non_contextual_creation=true The other solution described here: http://vkuzel.blogspot.com.cy/2016/03/spring-boot-jpa-hibernate-atomikos.html Disable feature detection by this undocumented parameter. Check the org.hibernate.engine.jdbc.internal.JdbcServiceImpl.configure method for more details. spring.jpa.properties.hibernate.temp.use_jdbc_metadata_defaults = false So you can also … Read more

How to resolve Unable to load authentication plugin ‘caching_sha2_password’ issue

Starting with MySQL 8.0.4, they have changed the default authentication plugin for MySQL server from mysql_native_password to caching_sha2_password. You can run the below command to resolve the issue. sample username / password => student / pass123 Refer the official page for details: MySQL Reference Manual

when to throw FileNotFoundException

Java has some controversy about its exceptions. It has two classes of exceptions. Checked and unchecked. Any exception extending from RuntimeException or Error is unchecked and does not need to be caught or explicitly declared as throwable in a method signature. FileNotFound is however a checked exception and must either be caught or declared as … Read more

Swing/Java: How to use the getText and setText string properly

You are setting the label text before the button is clicked to “txt”. Instead when the button is clicked call setText() on the label and pass it the text from the text field. Example:

What do F and D mean at the end of numeric literals?

Means that these numbers are doubles and floats, respectively. Assume you have and then you call the compiler might be stumped. That’s why you can say 5, 5f, or 5.0 to specify the type.

“Picked up JAVA_TOOL_OPTIONS: -javaagent:/usr/share/java/jayatanaag.jar” when starting the Scala interpreter

You can disable jayatana just for the current shell session by unsetting JAVA_TOOL_OPTIONS like so: That way it will still be enabled for applications needing it.

Tomcat 404 error: The origin server did not find a current representation for the target resource or is not willing to disclose that one exists

Problem solved, I’ve not added the index.html. Which is point out in the web.xml Note: a project may have more than one web.xml file. if there are another web.xml in src/main/webapp/WEB-INF Then you might need to add another index (this time index.jsp) to src/main/webapp/WEB-INF/pages/

Printing a java map Map – How?

I’m sure there’s some nice library that does this sort of thing already for you… But to just stick with the approach you’re already going with, Map#entrySet gives you a combined Object with the key and the value. So something like: will do what you’re after. If you’re using java 8, there’s also the new streaming approach.

Static Initialization Blocks

The non-static block: Gets called every time an instance of the class is constructed. The static block only gets called once, when the class itself is initialized, no matter how many objects of that type you create. Example: This prints:

NoClassDefFoundError in Java: com/google/common/base/Function

I had the same problem, and finally I found that I forgot to add the selenium-server-standalone-version.jar. I had only added the client jar, selenium-java-version.jar.

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