Category Archives: Java

Immutable objects

Most of the objects in Java are mutable. It means that their state/fields can be changed after the object was created. The examples of those are: ArrayList, Calendar, StringBuilder. Immutable objects An object is immutable if its state/fields cannot be … Continue reading

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Delete directory with contents in Java

Removing empty directory in Java is as simple as calling File.delete() (standard IO) or Files.delete() (NIO) method. However, if the folder is not empty (for example contains one or more files or subdirectories), these methods will refuse to remove it. … Continue reading

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How to delete file in Java

File management (good old CRUD: create, read, update, delete) is quite common operation in software development. In this short post I would like to present 2 ways of removing files in Java. Method available in every Java version Every Java … Continue reading

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Importing WSDL with Java and Maven

SOAP web services are often used in commercial software. If we plan to use existing SOAP web service, we should receive a WSDL file which defines the contract between the web service and its clients. This contract defines at least: … Continue reading

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Objects utility class in Java

Today I would like to quickly mention java.util.Objects class. The JavaDoc documentation for this class says: This class consists of static utility methods for operating on objects. These utilities include null-safe or null-tolerant methods for computing the hash code of … Continue reading

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Default and static methods in interfaces in Java 8

Before Java 8 interfaces could only contain static fields (usually simple constants) and abstract methods. Java 8 provided the ability to define concrete (default and static) methods in interfaces. This new language feature is used extensively in Java core packages. … Continue reading

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Database schema creation in JPA using SQL scripts

Recent versions of JPA provide a feature to automatically create the database objects (like tables, sequences or indexes), load initial data into database on application deployment; and also remove them after the application is undeployed. All that is needed is … Continue reading

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