- Binary Literals - In Java SE 7, the integral types (
byte
,short
,int
, andlong
) can also be expressed using the binary number system. To specify a binary literal, add the prefix0b
or0B
to the number.
- Underscores in Numeric Literals - Any number of underscore characters (
_
) can appear anywhere between digits in a numerical literal. This feature enables you, for example, to separate groups of digits in numeric literals, which can improve the readability of your code. - Strings in switch Statements - You can use the
String
class in the expression of aswitch
statement. - Type Inference for Generic Instance Creation - You can replace the type arguments required to invoke the constructor of a generic class with an empty set of type parameters (
<>
) as long as the compiler can infer the type arguments from the context. This pair of angle brackets is informally called the diamond. - Improved Compiler Warnings and Errors When Using Non-Reifiable Formal Parameters with Varargs Methods - The Java SE 7 complier generates a warning at the declaration site of a varargs method or constructor with a non-reifiable varargs formal parameter. Java SE 7 introduces the compiler option
-Xlint:varargs
and the annotations@SafeVarargs
and@SuppressWarnings({"unchecked", "varargs"})
to supress these warnings. - The try-with-resources Statement - The
try
-with-resources statement is atry
statement that declares one or more resources. A resource is an object that must be closed after the program is finished with it. Thetry
-with-resources statement ensures that each resource is closed at the end of the statement. Any object that implements the newjava.lang.AutoCloseable
interface or thejava.io.Closeable
interface can be used as a resource. The classesjava.io.InputStream
,OutputStream
,Reader
,Writer
,java.sql.Connection
,Statement
, andResultSet
have been retrofitted to implement theAutoCloseable
interface and can all be used as resources in atry
-with-resources statement. - Catching Multiple Exception Types and Rethrowing Exceptions with Improved Type Checking - A single
catch
block can handle more than one type of exception. In addition, the compiler performs more precise analysis of rethrown exceptions than earlier releases of Java SE. This enables you to specify more specific exception types in thethrows
clause of a method declaration.
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