How to extract all the links in selenium?

 package wdProgram;

import java.util.List;

import java.util.concurrent.TimeUnit;

import org.openqa.selenium.By;

import org.openqa.selenium.WebDriver;

import org.openqa.selenium.WebElement;

import org.openqa.selenium.chrome.ChromeDriver;

import org.testng.annotations.BeforeTest;

import org.testng.annotations.Test;

public class ExtractAllLinks {

WebDriver driver;

@BeforeTest

public void openBrowser() {

System.setProperty("webdriver.chrome.driver",

"D:\\Software\\Testing-Tools\\Selenium\\WebDriver\\Drivers\\IEChromeFirefox\\19092018\\chromedriver.exe");

driver = new ChromeDriver();

driver.manage().window().maximize();

driver.manage().timeouts().implicitlyWait(10, TimeUnit.SECONDS);

}

@Test

public void testExtractAllLinks() {

driver.get("http://localhost/uth/gadgetsgallery/catalog");

WebElement catBox = driver.findElement(By.xpath("//*[@id=\"left_sidebar\"]/div[1]/div[2]"));

List<WebElement> allLinks = catBox.findElements(By.tagName("a"));

System.out.println(allLinks.size());

for(int count=0;count<allLinks.size();count++) {

System.out.println(allLinks.get(count).getText());

allLinks.get(count).click();

System.out.println(driver.getTitle());

System.out.println(driver.getCurrentUrl());

driver.navigate().back();

catBox = driver.findElement(By.xpath("//*[@id=\"left_sidebar\"]/div[1]/div[2]"));

allLinks = catBox.findElements(By.tagName("a"));

}

}

}