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Android: java.lang.NullPointerException: Attempt to invoke virtual method ‘java.lang.String java.lang.Object.toString()’ on a null object reference

Facing a problem with a practice app I’m working on. I’m facing a NullPointerException problem relating to the toString method. Being new to android app development, I’m unsure of the exact cause even after my research into this. Hence I ask for someone who is more familiar with the stack trace to kindly help me out. Note: The error occurs

Jackson – Custom TypeId Resolver

I’ve been using a custom typeId resolver for one of my classes, so far I’ve been leaning on the annotation support: @JsonTypeInfo( use = JsonTypeInfo.Id.CUSTOM, include = JsonTypeInfo.As….

Cleaning up after changing the isolation level in JPA / EclipsLink EntityManager

I’m performing a transaction in JPA (EclipseLink) using a custom transaction isolation level, which I set on the underlying connection of the JPA EntityManager using this code: If I try to reset the isolation level to the old value after having committed the transaction, the underlying connection is null (entityManager.unwrap(Connection.class) returns null). I’m worried, if I just don’t reset the

When creating a Java class in IntelliJ: is there a wizard/menu to select the package and class to extend from?

One of the features I like of Eclipse is that when creating Java classes, a wizard is available to specify different properties for the class. Like its package, class to extend from…etc (see below in the screen cap). Does IntelliJ provide something similar? I created a class but the process wasn’t smooth. I had to…mark /java directory as Source Root…create