Java – Convert integer to string [duplicate]
There are multiple ways: String.valueOf(number) (my preference) “” + number (I don’t know how the compiler handles it, perhaps it is as efficient as the above) Integer.toString(number)
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What is the equivalent of the C++ Pair in Java?
In a thread on comp.lang.java.help, Hunter Gratzner gives some arguments against the presence of a Pair construct in Java. The main argument is that a class Pair doesn’t convey any semantics about the relationship between the two values (how do you know what “first” and “second” mean ?). A better practice is to write a very simple class, like the one … Read more
Unable to find valid certification path to requested target – error even after cert imported
Unfortunately – it could be many things – and lots of app servers and other java ‘wrappers’ are prone to play with properties and their ‘own’ take on keychains and what not. So it may be looking at something totally different. Short of truss-ing – I’d try: to see if that helps. Instead of ‘all’ … Read more
Unable to find valid certification path to requested target – error even after cert imported
Unfortunately – it could be many things – and lots of app servers and other java ‘wrappers’ are prone to play with properties and their ‘own’ take on keychains and what not. So it may be looking at something totally different. Short of truss-ing – I’d try: to see if that helps. Instead of ‘all’ … Read more
What exactly is Apache Camel?
If you have 5 to 10 minutes, I generally recommend people to read this Integration with Apache Camel by Jonathan Anstey. It’s a well written piece which gives a brief introduction to and overview of some of Camel’s concepts, and it implements a use case with code samples. In it, Jonathan writes: Apache Camel is an open … Read more
What is a NullPointerException, and how do I fix it?
4018 When you declare a reference variable (i.e., an object), you are really creating a pointer to an object. Consider the following code where you declare a variable of primitive type int: In this example, the variable x is an int and Java will initialize it to 0 for you. When you assign the value … Read more
How to use the toString method in Java?
From the Object.toString docs: Returns a string representation of the object. In general, the toString method returns a string that “textually represents” this object. The result should be a concise but informative representation that is easy for a person to read. It is recommended that all subclasses override this method. The toString method for class Object returns a string consisting of the name … Read more
&& (AND) and || (OR) in IF statements
No, it will not be evaluated. And this is very useful. For example, if you need to test whether a String is not null or empty, you can write: or, the other way around If we didn’t have ‘short-circuits’ in Java, we’d receive a lot of NullPointerExceptions in the above lines of code.
What is the difference between x86 and x64
x86 is for a 32-bit OS, and x64 is for a 64-bit OS
How to format strings in Java
In addition to String.format, also take a look java.text.MessageFormat. The format less terse and a bit closer to the C# example you’ve provided and you can use it for parsing as well. For example: A nicer example takes advantage of the varargs and autoboxing improvements in Java 1.5 and turns the above into a one-liner: MessageFormat is … Read more