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Tag: java

“unable to locate Spring NamespaceHandler” error

I’m creating a stand-alone Sava application with Spring, to handle the JDBC access. The application works fine on every test and I decided that I need a jar to be deployed our clients. They might not have spring in their classpath, so I used maven-assembly-plugin to handle the jar creation with dependen…

Content-Length header already present

I am using the Apache HttpClient (4.1) included in Android to execute a HttpPut. I have verified that I only have 1 content-length header. However, every time I send the request, I get a protocol exception about the Content-Length header already specified. Caused by: org.apache.http.ProtocolException: Content…

Is there an equivalent to memcpy() in Java?

I have a byte[] and would like to copy it into another byte[]. Maybe I am showing my simple ‘C’ background here, but is there an equivalent to memcpy() on byte arrays in Java? Answer You might try System.arraycopy or make use of array functions in the Arrays class like java.util.Arrays.copyOf. Bot…

Why do threads share the heap space?

Threads each have their own stack, but they share a common heap. Its clear to everyone that stack is for local/method variables & heap is for instance/class variables. What is the benefit of sharing heap among threads. There are several number of threads running simultaneously, so sharing memory can lead …

What version of javac built my jar?

How can I tell what version of the Java compiler was used to build a jar? I have a jar file, and it could have been built in any one of three JDKs. We need to know exactly which one, so we can certify compatibility. Is the compiler version embedded somewhere in the class files or jar? Answer You can’t