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Tag: java

Checking if a date exists or not in Java

Is there any predefined class in Java such that, if I pass it a date it should return if it is a valid date or not? For example if I pass it 31st of February of some year, then it should return false, and if the date exists then it should return me true, for any date of any year.

Does Java IO have a maximum file name length limit?

Different operating systems have different file name max lengths. Does Java have any limit on file name length when working with files? Answer Java has no maximum file name length, except obviously for the String max length limit (which is the array max length, i.e. Integer.MAX_VALUE). Maybe some JVMs have a …

when is a spring bean instantiated

In the above, when are the beans instantiated, when the ApplicationContext is created or when the getBean() is called? Answer Assuming the bean is a singleton, and isn’t configured for lazy initialisation, then it’s created when the context is started up. getBean() just fishes it out. Lazy-init be…

How can I add JAR files to the web-inf/lib folder in Eclipse?

I’m using Eclipse and I need to be able to add Java libraries (JAR files) into my web application’s WEB-INF/lib folder. How do I achieve this? Answer Add the jar file to your WEB-INF/lib folder. Right-click your project in Eclipse, and go to “Build Path > Configure Build Path” Add t…

Ultra-fast “Begins With” Query from Disk

I have a 40MB (too big for memory in this case) list of strings that I want to do “begins with” queries on to extract matches. Anyone know of a good data structure for this? Bonus points for an existing os java implementation. I would be willing to sacrifice “begins with” to just exact…