Java OOP; creating array of objects

I’d like to create an array of objects where 3 objects are from one class, and a 4th is from second class. In the first class I did the following: public class Pupil { public int n= 0; …

Flink ElasticsearchSinkFunction not serializable in non-static method, but serializable in static method

I have a piece of code that only works inside static methods. If I put the code in a static method, then call it from a non-static method, it works. Never heard of anything like this and couldn’t find …

How to assign values to Attributes by passing argument using from method?

I need to assign YEAR, MONTH, DAY attributes to values just only using one set method. therefore I pass DATE.YEAR, DATE.MONTH, DATE.DATE as an argument also with values by calling set method line by …

Using static methods with Spring Security to get current user details

I have a requirement to get the details of the current user who has been loggedIn. To get the details, we can use the SecurityContextHolder.getContext() and extract the details. According to, …

Why in Android documentation Activity classes have static modifier

If we open android documentation we will see that Activity classes have static modifier: public static class MainActivity extends Activity {…} I’m used to declaring Activities without static …

multiple constructors for final fields in java

I have some final fields in the class like class A { private final boolean a; private final boolean b; public A(boolean a){ this.a = a; } public A(boolean a, boolean b){ this.a = a; …

Mocking static methods with Mockito

I’ve written a factory to produce java.sql.Connection objects: public class MySQLDatabaseConnectionFactory implements DatabaseConnectionFactory { @Override public Connection getConnection() { …

Necessity of static block in Java

I found that in Java, there is a feature called static block, which includes code that is executed when a class is first loaded (I don’t understand what ‘loaded’ means, does it mean initialized?). Is …

How can I get a resource content from a static context?

I want to read strings from an xml file before I do much of anything else like setText on widgets, so how can I do that without an activity object to call getResources() on?

Getting the class name from a static method in Java

How can one get the name of the class from a static method in that class. For example public class MyClass { public static String getClassName() { String name = ????; // what goes here so …