How to Use Regular Expression in Java

Whether you’re coding, using a search engine, searching and replacing text in a text editor, or using the command-line utilities grep, sed, and awk in Linux, you’re using regular expressions (also known as “regex” or “regexp”). Yes, they’re everywhere.

A regular expression is a sequence of characters used to describe a text pattern. Working with regular expressions is rarely described as fun, but they are useful for various problems while coding a feature, such as finding and replacing operations with strings.

When coding a solution using regular expressions, you typically use the built-in libraries provided by the programming language you’re using. Java is no exception. It includes support for regular expressions using classes in the java.util.regex package.

In this article, you’ll learn how to use regular expressions to define a pattern for searching or manipulating strings in Java.

The what and why of regular expressions

So, what are regular expressions? Wikipedia defines a regular expression as “a sequence of characters that specifies a search pattern in text.”

For example, if you use the regular expression ab*, you’re issuing an instruction to match a string that has an a followed by zero or more b’s. So strings like ab, abc, abbc, etc. will match our regular expression. The asterisk symbol, *, denotes the number of times a character or a sequence of characters may occur.

Regular expressions make finding patterns in text much easier. Some high-level use cases include:

• Email validation
• Phone number validation
• Credit card number validation
• Password pattern matching
• String replacement

Regular expressions are also well-supported in many programming languages.

How to use regular expressions in Java

Supporting classes for regular expressions in Java are available in the java.util.regex package. As per Java’s documentation, the package primarily consists of the three classes below.

Pattern: The object of this class is a compiled representation of a regular expression. There are no public constructors available in this class, so you need to call the compile() static method to create an object.

Here are the different implementation details and method signature of the compile() method available in the Pattern class as per Java’s documentation.

/**
* Compiles the given regular expression into a pattern.
*
* @param  regex
*         The expression to be compiled
* @return the given regular expression compiled into a pattern
* @throws  PatternSyntaxException
*          If the expression's syntax is invalid
*/
public static Pattern compile(String regex) {
    return new Pattern(regex, 0);
}

/**
* Compiles the given regular expression into a pattern with the given
* flags.
* @param  regex
*         The expression to be compiled
*
* @param  flags
*         Match flags, a bit mask that may include
*         {@link #CASE_INSENSITIVE}, {@link #MULTILINE}, {@link #DOTALL},
*         {@link #UNICODE_CASE}, {@link #CANON_EQ}, {@link #UNIX_LINES},
*         {@link #LITERAL}, {@link #UNICODE_CHARACTER_CLASS}
*         and {@link #COMMENTS}
*
* @return the given regular expression compiled into a pattern with the given flags
*/
public static Pattern compile(String regex, int flags) {
    return new Pattern(regex, flags);
}

Matcher: This class also has no public constructor, and the object of this class is constructed by invoking the matcher() method on a Pattern class object. The Matcher object will match the given input against a given pattern.

PatternSyntaxException: This class throws an unchecked exception to indicate a syntax error in a regular-expression pattern.

The typical code flow of working with a regular expression in Java is shown below.

We first create a Pattern object by invoking its static compile() method, and then we pass it a pattern, i.e., string literal Java, as the first input parameter. The second input parameter, Pattern.CASE_INSENSITIVE, enables case-insensitive matching.

Next, we create an object of the Matcher class by calling the Pattern object’s matcher() method. We are also passing the text we want to check for matches: if there is a match, the program prints true, and false if there isn’t.

public class TestRegularExpressions {

    public static void main(String[] args) {
        Pattern pattern = Pattern.compile("Java", Pattern.CASE_INSENSITIVE);
        System.out.println(pattern.matcher("java").matches()); // prints true
        System.out.println(pattern.matcher("JAVA").matches()); // prints true
        System.out.println(pattern.matcher("javascript").matches()); // prints false
    }
}

Moreover, in Java, String class has methods for string manipulation using regular expressions. Here are some coding examples:

public class StringRegexOperations {
    public static void main(String[] args) {
        String str1 = "J A V A";
        System.out.println(str1.replaceAll("\\s", "")); // prints "JAVA"
        String str2 = "J,AVA";
        System.out.println(str2.replaceFirst(",", "")); // prints "JAVA"
        String str3 = "C,Java,Kotlin,C++";
        System.out.println(Arrays.stream(str3.split(","))
            .filter(s -> s.equals("Java")).findFirst().get()); // prints "Java"
        String str4 = "jane@okta.com";
        System.out.println(str4.matches("^[a-zA-Z0-9_!#$%&'*+/=?`{|}~^.-]+@[a-zA-Z0-9.-]+$")); // prints true
    }
}

While the preceding coding example is self-explanatory, here is a summary of methods available in the String class that accepts regex as one of its input parameters:

Method Name	What it does
replaceAll()	Replaces each substring of this string that matches the given regular expression with the given replacement.
replaceFirst()	Replaces the first substring of this string that matches the given regular expression with the given replacement.
split()	Splits this string around matches of the given regular expression.
matches()	Tells whether or not this string matches the given regular expression.

How to use regular expressions to validate email addresses and phone numbers

A common use case for regular expressions is to validate email addresses and phone numbers, which you’ll learn to do here.

import org.junit.jupiter.api.Test;

import java.util.regex.Matcher;
import java.util.regex.Pattern;

import static org.junit.jupiter.api.Assertions.assertFalse;
import static org.junit.jupiter.api.Assertions.assertTrue;

class DemoApplicationTests {
    /**
     * We will use the following test method `setUp()` that accepts two inputs, i.e. the regex pattern and the string to be searched in the given pattern.
     * @param inputRegex
     * @param searchString
     */
    boolean setUp(String inputRegex, String searchString) {
        Pattern p = Pattern.compile(inputRegex, Pattern.CASE_INSENSITIVE);
        Matcher m = p.matcher(searchString);
        return m.matches();
    }

    /**
     * The following test shows how to do email validation using classes available in the `java.util.regex` Java package against the valid input.
     * This test should pass.
     */
    @Test
    void when_email_is_valid() {
        assertTrue(setUp("[a-zA-Z0-9_+&*-]*@" + "okta.com$", "julia@okta.com"));
    }

    /**
     * And this test shows how to do so against the invalid input. This test should result in a failure.
     */
    @Test
    void when_email_is_invalid() {
        assertFalse(setUp("[a-zA-Z0-9_+&*-]*@" + "okta.com$", "julia@okta"));
    }

    /**
     * The following tests show how to do phone validation using classes available in the `java.util.regex` Java package.
     * It uses a basic regular expression to check if the number is a valid ten digit. Advanced use cases could also handle country codes and so forth.
     */
    @Test
    void when_phone_number_is_valid() {
        String regex = "^[0-9]{10}$";
        assertTrue(setUp("^[0-9]{10}$", "1234567890"));
    }

    /**
     * And this test shows how to do so against the invalid input. This test should result in a failure.
     */
    @Test
    void when_phone_number_is_invalid() {
        String regex = "^[0-9]{10}$";
        assertFalse(setUp("^[0-9]{10}$", "123456789"));
    }
}

Alternative resources for building and validating regular expressions

Several resources are available to help you with using regular expressions. Here are three relevant for Java.

Regexr

Regexr is an HTML/JS-based tool for creating, testing, and learning about regular expressions. It’s a good resource for building and validating patterns in the browser. One of the best features of Regexr is its Community Patterns feature, where you can search for patterns submitted by other users.

To use a community pattern, you must first select a pattern, click on its URL, or double-click the list to load the full pattern. You can also use the right arrow icon to load the expression or text. In the screenshot below, we have picked an existing community pattern for password validation. We have run some tests to ensure that it does proper password validation as per the regex.

GitHub Copilot

Thanks to GitHub Copilot, an AI tool developed by GitHub, you no longer have to write your own regular expressions.

The following screenshot shows Copilot suggesting a regex for email validation. In the IntelliJ Idea IDE, we can press TAB to accept the suggestion.

JavaVerbalExpressions

JavaVerbalExpressions is a library written in Java that helps to construct difficult regular expressions. You can add the following Maven dependency to add support for this library to your project.

<dependency>
    <groupId>ru.lanwen.verbalregex</groupId>
    <artifactId>java-verbal-expressions</artifactId>
    <version>1.8</version>
</dependency>

JavaVerbalExpressions uses a builder pattern to construct regex. Below is an example showing how to use it to play with regular expressions.

VerbalExpression testRegex = VerbalExpression.regex()
  .startOfLine().then("abc").or("def")
  .build();

String testString = "defzzz";

// Use VerbalExpression's test() method to test if parts of the string match the regex
testRegex.test(testString);       // true
testRegex.testExact(testString);  // false
testRegex.getText(testString);    // returns: def

Learn more about regular expressions in Java

Regular expressions aren’t exciting, but it’s useful to learn how to use them well. They’re also a valuable transferable skill that you won’t only use in Java. This article showed you how to use regular expressions to define a pattern for searching or manipulating strings in Java.

Original article sourced at: https://developer.okta.com

#java 

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Pdf2gerb: Perl Script Converts PDF Files to Gerber format

pdf2gerb

Perl script converts PDF files to Gerber format

Pdf2Gerb generates Gerber 274X photoplotting and Excellon drill files from PDFs of a PCB. Up to three PDFs are used: the top copper layer, the bottom copper layer (for 2-sided PCBs), and an optional silk screen layer. The PDFs can be created directly from any PDF drawing software, or a PDF print driver can be used to capture the Print output if the drawing software does not directly support output to PDF.

The general workflow is as follows:

1. Design the PCB using your favorite CAD or drawing software.
2. Print the top and bottom copper and top silk screen layers to a PDF file.
3. Run Pdf2Gerb on the PDFs to create Gerber and Excellon files.
4. Use a Gerber viewer to double-check the output against the original PCB design.
5. Make adjustments as needed.
6. Submit the files to a PCB manufacturer.

Please note that Pdf2Gerb does NOT perform DRC (Design Rule Checks), as these will vary according to individual PCB manufacturer conventions and capabilities. Also note that Pdf2Gerb is not perfect, so the output files must always be checked before submitting them. As of version 1.6, Pdf2Gerb supports most PCB elements, such as round and square pads, round holes, traces, SMD pads, ground planes, no-fill areas, and panelization. However, because it interprets the graphical output of a Print function, there are limitations in what it can recognize (or there may be bugs).

See docs/Pdf2Gerb.pdf for install/setup, config, usage, and other info.

---

pdf2gerb_cfg.pm

#Pdf2Gerb config settings:
#Put this file in same folder/directory as pdf2gerb.pl itself (global settings),
#or copy to another folder/directory with PDFs if you want PCB-specific settings.
#There is only one user of this file, so we don't need a custom package or namespace.
#NOTE: all constants defined in here will be added to main namespace.
#package pdf2gerb_cfg;

use strict; #trap undef vars (easier debug)
use warnings; #other useful info (easier debug)


##############################################################################################
#configurable settings:
#change values here instead of in main pfg2gerb.pl file

use constant WANT_COLORS => ($^O !~ m/Win/); #ANSI colors no worky on Windows? this must be set < first DebugPrint() call

#just a little warning; set realistic expectations:
#DebugPrint("${\(CYAN)}Pdf2Gerb.pl ${\(VERSION)}, $^O O/S\n${\(YELLOW)}${\(BOLD)}${\(ITALIC)}This is EXPERIMENTAL software.  \nGerber files MAY CONTAIN ERRORS.  Please CHECK them before fabrication!${\(RESET)}", 0); #if WANT_DEBUG

use constant METRIC => FALSE; #set to TRUE for metric units (only affect final numbers in output files, not internal arithmetic)
use constant APERTURE_LIMIT => 0; #34; #max #apertures to use; generate warnings if too many apertures are used (0 to not check)
use constant DRILL_FMT => '2.4'; #'2.3'; #'2.4' is the default for PCB fab; change to '2.3' for CNC

use constant WANT_DEBUG => 0; #10; #level of debug wanted; higher == more, lower == less, 0 == none
use constant GERBER_DEBUG => 0; #level of debug to include in Gerber file; DON'T USE FOR FABRICATION
use constant WANT_STREAMS => FALSE; #TRUE; #save decompressed streams to files (for debug)
use constant WANT_ALLINPUT => FALSE; #TRUE; #save entire input stream (for debug ONLY)

#DebugPrint(sprintf("${\(CYAN)}DEBUG: stdout %d, gerber %d, want streams? %d, all input? %d, O/S: $^O, Perl: $]${\(RESET)}\n", WANT_DEBUG, GERBER_DEBUG, WANT_STREAMS, WANT_ALLINPUT), 1);
#DebugPrint(sprintf("max int = %d, min int = %d\n", MAXINT, MININT), 1); 

#define standard trace and pad sizes to reduce scaling or PDF rendering errors:
#This avoids weird aperture settings and replaces them with more standardized values.
#(I'm not sure how photoplotters handle strange sizes).
#Fewer choices here gives more accurate mapping in the final Gerber files.
#units are in inches
use constant TOOL_SIZES => #add more as desired
(
#round or square pads (> 0) and drills (< 0):
    .010, -.001,  #tiny pads for SMD; dummy drill size (too small for practical use, but needed so StandardTool will use this entry)
    .031, -.014,  #used for vias
    .041, -.020,  #smallest non-filled plated hole
    .051, -.025,
    .056, -.029,  #useful for IC pins
    .070, -.033,
    .075, -.040,  #heavier leads
#    .090, -.043,  #NOTE: 600 dpi is not high enough resolution to reliably distinguish between .043" and .046", so choose 1 of the 2 here
    .100, -.046,
    .115, -.052,
    .130, -.061,
    .140, -.067,
    .150, -.079,
    .175, -.088,
    .190, -.093,
    .200, -.100,
    .220, -.110,
    .160, -.125,  #useful for mounting holes
#some additional pad sizes without holes (repeat a previous hole size if you just want the pad size):
    .090, -.040,  #want a .090 pad option, but use dummy hole size
    .065, -.040, #.065 x .065 rect pad
    .035, -.040, #.035 x .065 rect pad
#traces:
    .001,  #too thin for real traces; use only for board outlines
    .006,  #minimum real trace width; mainly used for text
    .008,  #mainly used for mid-sized text, not traces
    .010,  #minimum recommended trace width for low-current signals
    .012,
    .015,  #moderate low-voltage current
    .020,  #heavier trace for power, ground (even if a lighter one is adequate)
    .025,
    .030,  #heavy-current traces; be careful with these ones!
    .040,
    .050,
    .060,
    .080,
    .100,
    .120,
);
#Areas larger than the values below will be filled with parallel lines:
#This cuts down on the number of aperture sizes used.
#Set to 0 to always use an aperture or drill, regardless of size.
use constant { MAX_APERTURE => max((TOOL_SIZES)) + .004, MAX_DRILL => -min((TOOL_SIZES)) + .004 }; #max aperture and drill sizes (plus a little tolerance)
#DebugPrint(sprintf("using %d standard tool sizes: %s, max aper %.3f, max drill %.3f\n", scalar((TOOL_SIZES)), join(", ", (TOOL_SIZES)), MAX_APERTURE, MAX_DRILL), 1);

#NOTE: Compare the PDF to the original CAD file to check the accuracy of the PDF rendering and parsing!
#for example, the CAD software I used generated the following circles for holes:
#CAD hole size:   parsed PDF diameter:      error:
#  .014                .016                +.002
#  .020                .02267              +.00267
#  .025                .026                +.001
#  .029                .03167              +.00267
#  .033                .036                +.003
#  .040                .04267              +.00267
#This was usually ~ .002" - .003" too big compared to the hole as displayed in the CAD software.
#To compensate for PDF rendering errors (either during CAD Print function or PDF parsing logic), adjust the values below as needed.
#units are pixels; for example, a value of 2.4 at 600 dpi = .0004 inch, 2 at 600 dpi = .0033"
use constant
{
    HOLE_ADJUST => -0.004 * 600, #-2.6, #holes seemed to be slightly oversized (by .002" - .004"), so shrink them a little
    RNDPAD_ADJUST => -0.003 * 600, #-2, #-2.4, #round pads seemed to be slightly oversized, so shrink them a little
    SQRPAD_ADJUST => +0.001 * 600, #+.5, #square pads are sometimes too small by .00067, so bump them up a little
    RECTPAD_ADJUST => 0, #(pixels) rectangular pads seem to be okay? (not tested much)
    TRACE_ADJUST => 0, #(pixels) traces seemed to be okay?
    REDUCE_TOLERANCE => .001, #(inches) allow this much variation when reducing circles and rects
};

#Also, my CAD's Print function or the PDF print driver I used was a little off for circles, so define some additional adjustment values here:
#Values are added to X/Y coordinates; units are pixels; for example, a value of 1 at 600 dpi would be ~= .002 inch
use constant
{
    CIRCLE_ADJUST_MINX => 0,
    CIRCLE_ADJUST_MINY => -0.001 * 600, #-1, #circles were a little too high, so nudge them a little lower
    CIRCLE_ADJUST_MAXX => +0.001 * 600, #+1, #circles were a little too far to the left, so nudge them a little to the right
    CIRCLE_ADJUST_MAXY => 0,
    SUBST_CIRCLE_CLIPRECT => FALSE, #generate circle and substitute for clip rects (to compensate for the way some CAD software draws circles)
    WANT_CLIPRECT => TRUE, #FALSE, #AI doesn't need clip rect at all? should be on normally?
    RECT_COMPLETION => FALSE, #TRUE, #fill in 4th side of rect when 3 sides found
};

#allow .012 clearance around pads for solder mask:
#This value effectively adjusts pad sizes in the TOOL_SIZES list above (only for solder mask layers).
use constant SOLDER_MARGIN => +.012; #units are inches

#line join/cap styles:
use constant
{
    CAP_NONE => 0, #butt (none); line is exact length
    CAP_ROUND => 1, #round cap/join; line overhangs by a semi-circle at either end
    CAP_SQUARE => 2, #square cap/join; line overhangs by a half square on either end
    CAP_OVERRIDE => FALSE, #cap style overrides drawing logic
};
    
#number of elements in each shape type:
use constant
{
    RECT_SHAPELEN => 6, #x0, y0, x1, y1, count, "rect" (start, end corners)
    LINE_SHAPELEN => 6, #x0, y0, x1, y1, count, "line" (line seg)
    CURVE_SHAPELEN => 10, #xstart, ystart, x0, y0, x1, y1, xend, yend, count, "curve" (bezier 2 points)
    CIRCLE_SHAPELEN => 5, #x, y, 5, count, "circle" (center + radius)
};
#const my %SHAPELEN =
#Readonly my %SHAPELEN =>
our %SHAPELEN =
(
    rect => RECT_SHAPELEN,
    line => LINE_SHAPELEN,
    curve => CURVE_SHAPELEN,
    circle => CIRCLE_SHAPELEN,
);

#panelization:
#This will repeat the entire body the number of times indicated along the X or Y axes (files grow accordingly).
#Display elements that overhang PCB boundary can be squashed or left as-is (typically text or other silk screen markings).
#Set "overhangs" TRUE to allow overhangs, FALSE to truncate them.
#xpad and ypad allow margins to be added around outer edge of panelized PCB.
use constant PANELIZE => {'x' => 1, 'y' => 1, 'xpad' => 0, 'ypad' => 0, 'overhangs' => TRUE}; #number of times to repeat in X and Y directions

# Set this to 1 if you need TurboCAD support.
#$turboCAD = FALSE; #is this still needed as an option?

#CIRCAD pad generation uses an appropriate aperture, then moves it (stroke) "a little" - we use this to find pads and distinguish them from PCB holes. 
use constant PAD_STROKE => 0.3; #0.0005 * 600; #units are pixels
#convert very short traces to pads or holes:
use constant TRACE_MINLEN => .001; #units are inches
#use constant ALWAYS_XY => TRUE; #FALSE; #force XY even if X or Y doesn't change; NOTE: needs to be TRUE for all pads to show in FlatCAM and ViewPlot
use constant REMOVE_POLARITY => FALSE; #TRUE; #set to remove subtractive (negative) polarity; NOTE: must be FALSE for ground planes

#PDF uses "points", each point = 1/72 inch
#combined with a PDF scale factor of .12, this gives 600 dpi resolution (1/72 * .12 = 600 dpi)
use constant INCHES_PER_POINT => 1/72; #0.0138888889; #multiply point-size by this to get inches

# The precision used when computing a bezier curve. Higher numbers are more precise but slower (and generate larger files).
#$bezierPrecision = 100;
use constant BEZIER_PRECISION => 36; #100; #use const; reduced for faster rendering (mainly used for silk screen and thermal pads)

# Ground planes and silk screen or larger copper rectangles or circles are filled line-by-line using this resolution.
use constant FILL_WIDTH => .01; #fill at most 0.01 inch at a time

# The max number of characters to read into memory
use constant MAX_BYTES => 10 * M; #bumped up to 10 MB, use const

use constant DUP_DRILL1 => TRUE; #FALSE; #kludge: ViewPlot doesn't load drill files that are too small so duplicate first tool

my $runtime = time(); #Time::HiRes::gettimeofday(); #measure my execution time

print STDERR "Loaded config settings from '${\(__FILE__)}'.\n";
1; #last value must be truthful to indicate successful load


#############################################################################################
#junk/experiment:

#use Package::Constants;
#use Exporter qw(import); #https://perldoc.perl.org/Exporter.html

#my $caller = "pdf2gerb::";

#sub cfg
#{
#    my $proto = shift;
#    my $class = ref($proto) || $proto;
#    my $settings =
#    {
#        $WANT_DEBUG => 990, #10; #level of debug wanted; higher == more, lower == less, 0 == none
#    };
#    bless($settings, $class);
#    return $settings;
#}

#use constant HELLO => "hi there2"; #"main::HELLO" => "hi there";
#use constant GOODBYE => 14; #"main::GOODBYE" => 12;

#print STDERR "read cfg file\n";

#our @EXPORT_OK = Package::Constants->list(__PACKAGE__); #https://www.perlmonks.org/?node_id=1072691; NOTE: "_OK" skips short/common names

#print STDERR scalar(@EXPORT_OK) . " consts exported:\n";
#foreach(@EXPORT_OK) { print STDERR "$_\n"; }
#my $val = main::thing("xyz");
#print STDERR "caller gave me $val\n";
#foreach my $arg (@ARGV) { print STDERR "arg $arg\n"; }

---

Download Details:

Author: swannman
Source Code: https://github.com/swannman/pdf2gerb

License: GPL-3.0 license

#perl 

How to Install OpenJDK 11 on CentOS 8

What is OpenJDK?

OpenJDk or Open Java Development Kit is a free, open-source framework of the Java Platform, Standard Edition (or Java SE). It contains the virtual machine, the Java Class Library, and the Java compiler. The difference between the Oracle OpenJDK and Oracle JDK is that OpenJDK is a source code reference point for the open-source model. Simultaneously, the Oracle JDK is a continuation or advanced model of the OpenJDK, which is not open source and requires a license to use.

In this article, we will be installing OpenJDK on Centos 8.

#tutorials #alternatives #centos #centos 8 #configuration #dnf #frameworks #java #java development kit #java ee #java environment variables #java framework #java jdk #java jre #java platform #java sdk #java se #jdk #jre #open java development kit #open source #openjdk #openjdk 11 #openjdk 8 #openjdk runtime environment

Mad Libs: Using regular expressions

From Tiny Python Projects by Ken Youens-Clark

Everyone loves Mad Libs! And everyone loves Python. This article shows you how to have fun with both and learn some programming skills along the way.

---

Take 40% off Tiny Python Projects by entering fccclark into the discount code box at checkout at manning.com.

---

When I was a wee lad, we used to play at Mad Libs for hours and hours. This was before computers, mind you, before televisions or radio or even paper! No, scratch that, we had paper. Anyway, the point is we only had Mad Libs to play, and we loved it! And now you must play!

We’ll write a program called mad.py  which reads a file given as a positional argument and finds all the placeholders noted in angle brackets like <verb>  or <adjective> . For each placeholder, we’ll prompt the user for the part of speech being requested like “Give me a verb” and “Give me an adjective.” (Notice that you’ll need to use the correct article.) Each value from the user replaces the placeholder in the text, and if the user says “drive” for “verb,” then <verb>  in the text replaces with drive . When all the placeholders have been replaced with inputs from the user, print out the new text.

#python #regular-expressions #python-programming #python3 #mad libs: using regular expressions #using regular expressions

Going Beyond Java 8: Local Variable Type Inference (var) - DZone Java

According to some surveys, such as JetBrains’s great survey, Java 8 is currently the most used version of Java, despite being a 2014 release.

What you are reading is one in a series of articles titled ‘Going beyond Java 8,’ inspired by the contents of my book, Java for Aliens. These articles will guide you step-by-step through the most important features introduced to the language, starting from version 9. The aim is to make you aware of how important it is to move forward from Java 8, explaining the enormous advantages that the latest versions of the language offer.

In this article, we will talk about the most important new feature introduced with Java 10. Officially called local variable type inference, this feature is better known as the **introduction of the word **var. Despite the complicated name, it is actually quite a simple feature to use. However, some observations need to be made before we can see the impact that the introduction of the word var has on other pre-existing characteristics.

#java #java 11 #java 10 #java 12 #var #java 14 #java 13 #java 15 #verbosity

Lambda Expression in Java 8

In this blog we will understand what is the lambda expression and why we need lambda expression and how we use lambda and about the functional interface.

What is Lambda Expression :

• It is an anonymous function.
• Not having name
• No return type and no modifiers.

#functional programming #java #functional java #java #java 8 #java8 #lambda expressions in java