7 It is the Bitwise xor operator in java which results 1 for different value of bit (ie 1 ^ 0 = 1) and 0 for same value of bit (ie 0 ^ 0 = 0) when a number is written in binary form. ex :- To use your example: The binary representation of 5 is 0101. The binary representation of 4 is 0100.
In Java Persistence API you use them to map a Java class with database tables. For example @Table () Used to map the particular Java class to the date base table. @Entity Represents that the class is an entity class. Similarly you can use many annotations to map individual columns, generate ids, generate version, relationships etc.
Not only in Java, this syntax is available within PHP, Objective-C too. In the following link it gives the following explanation, which is quiet good to understand it: A ternary operator is some operation operating on 3 inputs. It's a shortcut for an if-else statement, and is also known as a conditional operator. In Perl/PHP it works as:
While hunting through some code I came across the arrow operator, what exactly does it do? I thought Java did not have an arrow operator. return (Collection<Car>) CollectionUtils.select(list...
JAVA_HOME and PATH are different, I didn't say point JAVA_HOME to the jre/bin directory. Try making sure that the PATH environment variable includes the jre/bin directory. For example, type java from the command prompt, does that work?
Since java.lang.String class override equals method, It return true if two String object contains same content but == will only return true if two references are pointing to same object. Here is an example of comparing two Strings in Java for equality using == and equals() method which will clear some doubts:
I always thought that && operator in Java is used for verifying whether both its boolean operands are true, and the & operator is used to do Bit-wise operations on two integer types.
java -Xmx1024m filename what does -Xmx mean?see here: Java Tool Doc, it says, -Xmxn Specify the maximum size, in bytes, of the memory allocation pool. This value must a multiple of 1024 greater than 2MB. Append the letter k or K to indicate kilobytes, or m or M to indicate megabytes. The default value is 64MB. The upper limit for this value will be approximately 4000m on Solaris 7 and Solaris ...
From Oracle's documentation: Note that the JVM uses more memory than just the heap. For example Java methods, thread stacks and native handles are allocated in memory separate from the heap, as well as JVM internal data structures.
