How to check if my string is equal to null?

As further comment, you should be aware of this term in the equals contract: From Object.equals(Object): For any non-null reference value x, x.equals(null) should return false. The way to compare with null is to use x == null and x != null. Moreover, x.field and x.method() throws NullPointerException if x == null.

copy a 2d array in java

There are two good ways to copy array is to use clone and System.arraycopy(). Here is how to use clone for 2D case: For System.arraycopy(), you use: I don’t have a benchmark but I can bet with my 2 cents that they are faster and less mistake-prone than doing it yourself. Especially, System.arraycopy() as it is implemented in native code. Hope this … Read more

java string cannot be converted to boolean error

You are currently assigning the value M to SystemOfMeasure, but if or else if conditions expect a boolean expression, NOT an assignment. So, you need to use .equals() method (which returns true/false) for string comparisons like SystemOfMeasure.equals(“M”) as shown below: Also, remember that, you need to follow the java naming standards like lower case for variable names like systemOfMeasure

Spring Maven clean error – The requested profile “pom.xml” could not be activated because it does not exist

The warning message means that you somehow passed -P pom.xml to Maven which means “there is a profile called pom.xml; find it and activate it”. Check your environment and your settings.xml for this flag and also look at all <profile> elements inside the various XML files. Usually, mvn help:effective-pom is also useful to see what the real POM would look like. Now the error … Read more

What exactly is a Maven Snapshot and why do we need it?

A snapshot version in Maven is one that has not been released. The idea is that before a 1.0 release (or any other release) is done, there exists a 1.0-SNAPSHOT. That version is what might become 1.0. It’s basically “1.0 under development”. This might be close to a real 1.0 release, or pretty far (right after the 0.9 release, for example). The difference between a “real” version and a … Read more

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