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Tag: java

Idiomatic way to use for-each loop given an iterator?

When the enhanced for loop (foreach loop) was added to Java, it was made to work with a target of either an array or Iterable. That works great for Collection classes that only implement one type of iteration, and thus have a single iterator() method. But I find myself incredibly frustrated the odd time I wan…

Search for a word in a String

If I am looking for a particular word inside a string, for example, in the string “how are you” I am looking for “are”. Would a regular indexOf() work faster and better or a Regex match() Which of the two methods above is a better way of looking for a string inside another string? Or i…

Converting from Integer, to BigInteger

I was wondering if there was any way to convert a variable of type Integer, to BigInteger. I tried typecasting the Integer variable, but i get an error that says inconvertible type. Answer The method you want is BigInteger#valueOf(long val). E.g., Making a String first is unnecessary and undesired.

How to clean up ThreadLocals

Does any one have an example how to do this? Are they handled by the garbage collector? I’m using Tomcat 6. Answer The javadoc says this: “Each thread holds an implicit reference to its copy of a thread-local variable as long as the thread is alive and the ThreadLocal instance is accessible; after…

Difference using @Id and @EmbeddedId for a compound key

I’ve created an entity that uses @Id to point to an @Embeddable compound key. Everything I believe works fine as is. However, after switching @Id to @EmbeddedId everything continues to work fine as far as I can tell. Before: After: Is there a difference between using the @Id and @EmbeddedId annotations …