Page Comparison

Default imports

• http://java.io .*

• java.lang.*

• java.math.BigDecimal

• java.math.BigInteger

• java.net.*

• java.util.*

• groovy.lang.*

• groovy.util.*

• java.lang.*

All other packages have to be mentioned clearly to import them into java class file

Extra

keywords

• as, define, trait

• are extra keywords

In Java we cannot use these keywords.

Default access modifier

Default access modifier is public i.e. if you don’t specify access modifier for fields, methods or

classes, it becomes package-private.

Default access modifier is package.

Getters and

setters

Getters and setters are automatically generated for class members.

You need to provide getters and setters

methods for fields, especially if you

follow Java Beans naming convention and use tools and libraries, which uses Reflection to dynamically access and mutate bean properties.

Semicolons

Semicolons (;) are optional, use them only if you like or if you want to write more than one statement in one line.

Semicolons are mandatory at the end of a line.

For loop

Groovy

loop declaration is much easier,

e.g.:

for(j in 0..4){ print j }
0.upto(3) { print "$it" }
4.times{ print "$it" }

There is only one way to declare

a loop:

for(int i=0;i<=5;i++){
  System.out.println(i);
}

Safe

navigation operator

Safe Navigation Operator (?.) is used to avoid a NullPointerException.

String str = null;
println  str?.reverse()

We have to perform some operation to check the null object, to avoid null pointer exception.

String str = null;
if(str != null){
    System.out.println(str.reverse());
}

The main() method

Groovy is a

scripting language, there’s automatically a wrapping class called Script for every program.

Main method is needed to make a class executable.

Array

declaration

Square brackets can be used.

String[]

testArray

=

["A",

"B",

"C"]

Curly braces have to be used

.

String[]

testArray

=

{"A",

"B",

"C"};

Data types

Everything is an object and uses only object, hence no concept of autoboxing or unboxing

.

Primitive data types and wrapper classes to perform boxing and unboxing implicitly or explicitly.