I’m new to Java. I’ve only been programming it for about a year. What does Spring mean by the use of templates? In Spring, there is jdbc-templates, jms-templates etc.. What are template classes in java? Are they a special kind of design pattern or what? Thank you in advance. Answer They are called…
Get URL(link) of a public S3 object programmatically
I am storing one public object in AWS S3 bucket using given java API in my server Now i need to return back the public URL of the S3 object to my client Till now i have’nt found any API call that can return the public URL(or link field) of a S3 object Is there any way to get the
Query creation in Spring Data – dynamic where clause
Is there a way in Spring data to dynamically form the where clause? What I want to do is have a method (which is like the findBy / get method) which runs a WHERE and AND using the mentioned properties which are NOT NULL. For example, Our method looks something like this Thanks. Answer Take a look at JPA Speci…
Load random Image from a directory using javafx
How can I load a random image from a directory using javafx, (the files located in the directory have different names) Currently I am using the following to load a specific file Answer Thanks to Patrick I came up with a short version:
How to use PostgreSQL hstore/json with JdbcTemplate
Is there a way to use PostgreSQL json/hstore with JdbcTemplate? esp query support. for eg: hstore: for Json Answer Although quite late for an answer (for the insert part), I hope it might be useful someone else: Take the key/value pairs in a HashMap: use one of the following way to insert them to PostgreSQL: …
Why can’t custom comparator be used with hashSet to check duplicate objects
I want to use a custom comparator to filter duplicate objects from a HashSet. In the Mobile class, I have defined a non-static nested Comparator class for comparing. The criterium which is used by this comparator is the id field of the Mobile object. Even though it works perfectly for a TreeSet, Eclipse shows…
What is the advantage of using scala pattern matching instead of java switch case?
Everybody says that pattern matching is a great feature in functional languages. Why? Can’t I simple use ifs and switch cases for everything? I’d like to understand the advantages of using pattern matching instead of regular procedural programming ifs and switch cases Answer I’d first like t…
Minimum number of node in AVL tree?
I know the formula of finding minimum number of node in a AVL tree is S(h) = S(h-1) + S(h-2) + 1 However, I don’t really get how to use this function, say if we have a AVL height of 6. The answer tells me that Minimum = 7 + 4 + 1 =12. But how do you get this
Use processing in Java application
I downloaded processing from http://processing.org. How is it possible to use porcessing in my Java application. I want drawing stuff depending on the logic in my Java application. To avoid the drawing in Java I want to use processing instead. Answer Piece of cake, First, In your IDE (eg Netbeans) first inclu…
LOG4J in Android
I have a Java Project with a lot of files, which is using LOG4J. Now I am trying to Port it to the Android platform. Is it possible to reuse the code as it is, with LOG4J function calls? Current understanding: Property configuration won’t work (beans dependency) I tried with LOG4J for Android and SL4J L…