Why doesn’t this code throw an ArithmeticException? Take a look: public class NewClass { public static void main(String[] args) { // TODO code application logic here double tab[] =…
MySQL Batchupdate() with ON DUPLICATE KEY UPDATE
I am using batchUpdate() to insert multiple records in a table. As per the requirement, if there is a duplicate value for a primary key while inserting it should be updated with the latest received data, hence I was trying to use ON DUPLICATE KEY UPDATE in INSERT statement. The ON DUPLICATE KEY UPDATE works good when I use a
Why can I not use “super” variable from a static context, even though “super” refers to the parent class and NOT a class instance, unlike “this”?
I’m talking java language. Variable “this”, when used inside a class, refers to the current instance of that class, which means you cannot use “this” inside a static method. But “super”, when used inside a class, refers to the superclass of that class, not an instance of the superclass, which should mean that you can use “super” inside a static
Eclipse autogenerated toString() method
As par as I know concatinate String using + sign is not a good practice when you have large number of String. But when I check on eclipse generated toString() method (Write click on source file -> …
Setting file permissions returns FALSE always
The code: File dir = new File(path); boolean rc1 = dir.setExecutable(true, false); boolean rc2 = dir.setReadable(true, false); boolean rc3 = dir.setWritable(true, false); if (!rc1 || !rc2 || !rc3){ …
Using a generic class to perform basic arithmetic operations
I want to perform basic arithmetic operations like addition, subtraction, multiplication and division using only one generic method per operation for wrapper types like Integer, Float, Double … (excluding BigDecimal and BigInteger). I have tried to do something like the following (for addition) using a generic class. It issues a compile-time error, operator + cannot be applied to E,E Is
Java Read Large Text File With 70million line of text
I have a big test file with 70 million lines of text. I have to read the file line by line. I used two different approaches: InputStreamReader isr = new InputStreamReader(new FileInputStream(FilePath),…
alternative to GrantedAuthorityImpl() class
I want an alternative to GrantedAuthorityImpl() class. I want this in spring security implementation. GrantedAuthorityImpl() class is deprecated. Hence I want an alternative solution to it. My code : …
How to create Java gradle project
How to create Java Gradle project from command line? It should create standard maven folder layout like on the picture below. UPDATE: .1. From http://www.gradle.org/docs/current/userguide/…
What is difference between CrudRepository and JpaRepository interfaces in Spring Data JPA?
What is the difference between CrudRepository and JpaRepository interfaces in Spring Data JPA? When I see the examples on the web, I see them there used kind of interchangeably. What is the …