java7 Features

• try with resource statement
• Suppressed Exception
• Catching multiple Exceptions
• java.util.Objects class & null check
• @SafeVarargs indicates will not couse the heap polution
• The new interfaces & classes from java.nio.file.*
• String in switch statement
• Type inference or Diamond operator

Java8 Features

• Default methods in interfaces aka defender methods or virtual extension methods
• static methods in interfaces

Terminal Operations - groupingBy()

• groupingBy collector is equivalent to the groupby clause in sql
• used to group the elements based on a property
• The ouput of groupingBy() is going to be a Map<K, V>
• There are three different version of groupingBy()
  • goupingBy(classifier)
  • groupingBy(classifier, downstream)

Map<Integer, Integer> deptSalaryMap = employees.stream()
                .collect(groupingBy(Employee::getDepartmentId, summingInt(Employee::getSalary)));

• groupingBy(classifier, supplier, downstream)

Stream API - Short Circuiting

Examples of Short Circuiting:
Example 1:
if(boolean1 && boolean2){ //AND
//body
}

If the first expression evaluates to false then the second expression
wont even execute.
Example 2:
if(boolean1 || boolean2){ //OR
//body
}

If the first expression evaluates to true then the second expression
wont even execute.

Stream API short circuit functions

• limit()
• findFirst()
• findAny()
• anyMatch()
• allMatch()
• noneMatch()

All these functions does not have to iterate the whole stream to evaluate the result.