Java Developer Interview Questions
In your interview for a Java developer position, be prepared to answer technical questions that test your understanding of Java basics. Interviewers may also ask open-ended questions to assess your coding and problem-solving abilities. Prepare for non-technical questions that focus on time management, interpersonal communication and your work ethic.
Top Java Developer Interview Questions & How to Answer
Here are three Java developer interview questions and tips on how to answer them:
Question No. 1: What is the difference between Hashtable and HashMap in Java?
How to answer: Interviewers use technical questions to assess your formal training and understanding of the Java programming language. Use your answer to demonstrate your communication skills. Even if you have been coding for some time, it can be helpful to review Java basics before your interview.
Question No. 2: Write a program to determine if 243 is an Armstrong number.
How to answer: Interviewers use open-ended questions to test your coding skills. This question allows the employer to assess your ability to solve a problem using a Java algorithm. Explain your thinking process as you use a code editor or whiteboard to solve the problem.
Question No. 3: How do you produce quality code when you have several Java projects to complete at once?
How to answer: Java developers often juggle multiple projects at the same time. Interviewers use questions such as this to test your time-management and organisational skills. Employers are also trying to assess your commitment to quality work. If you have experience as a developer, include examples from your work history that demonstrate high-quality work and effective time management.
attributes of <tr> tag
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please let me know if anyone got Job
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36. If you get call then follow this interview experience
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How many of you waiting after 3rd round
Coding test: 1. Given a string, find out if there's repeat characters in it. 2. SQL. Given a Customer table and a Payment table (with Customer ID as primary and foreign key), write a query to output a list of customers who have not paid their bills in the last 3 months.
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Did well on the first Java coding test. Solution using Hashset. Not so well on the SQL query. Able to give a query, but a few errors in it I am sure. Also there was a second questions regarding the SQL query, which we didn't have time to get to. So that was another bad thing. I am pretty sure I did not pass. But good learning experience. Less
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import java.util.*; public class test { public static void main(String[] args) { String str = "abdc"; char[] arr = str.toCharArray(); HashSet set = new HashSet(); for (char i : arr ) { set.add(i); } if((set.size()) == (arr.length)) System.out.println("unique character"); else System.out.println("repetition"); } } Less
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Write a program to print * * * * * * * * * * * * * * * * * * * * * * * * * * * * * with minimum number of variable use
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class StarPrint { public static void main (String[] args) throws java.lang.Exception { int i = 0, j = 0; for( i = 5; i > 0; i-- ){ for( j = 0; j < 5 - i; j++) System.out.print(" "); for( j = 0; j < i; j++ ) System.out.print("* "); System.out.println();} for( i = 3; i <= 6; i++ ){ for( j = 0; j <= 5 - i; j++) System.out.print(" "); for( j = 1; j < i; j++ ) System.out.print("* "); System.out.println(); } } } Less
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public class Check { public static void main(String[] args) { int limit = 5; // Specify the number of lines as limit and check output int i=0,j=0; for(i=0;ilimit-i;j--)System.out.print(" "); for(j=limit;j>i;j--)System.out.print("* "); System.out.println(); } j=limit; for(;limit>1;limit--){ for(i=2;ilimit-2;i--)System.out.print("* "); System.out.println(); } } } Less
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In the previous solution, the LESS THAN and GREATER THAN symbols have nit been parsed. public class Check { public static void main(String[] args) { int limit = 9; int i=0,j=0; for(i=0;i limit-i;j--)System.out.print(" "); for(j=limit;j > i;j--)System.out.print("* "); System.out.println(); } j=limit; for(;limit > 1;limit--){ for(i=2;i limit-2;i--)System.out.print("* "); System.out.println(); } } } Less
Write a program for odd input the pattern output will as below n=1 *-* n=3 ***** *** *---* *** *****
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import java.util.Scanner; public class Pattern{ public static void main(String[] args) { Scanner sc=new Scanner(System.in); int n=sc.nextInt(); for(int i=n;i>=2;i--){ for(int j=1;j<=2*n-(i-1);j++){ System.out.print(" "); } for(int k=1;k<=2*i-1;k++){ System.out.print("*"); } System.out.println(); } for(int i=1;i<=n-1;i++){ System.out.print(" "); } System.out.print("*"); for(int i=1;i<=n;i++){ System.out.print("-"); } System.out.print("*"); System.out.println(); for(int i=2;i<=n;i++){ for(int j=1;j<=n-i;j++){ System.out.print(" "); } for(int k=1;k<=2*i-1;k++){ System.out.print("*"); } System.out.println(); } } } Less
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import java.util.Scanner; class New3 { public static void main(String ... args) { Scanner sc =new Scanner(System.in); int n=sc.nextInt(); for(int j=n,p=1;j>=2;j--,p++) { for(int i=1;i<=n+p;i++) System.out.print(" "); for(int k=1;k<=2*j-1;k++) System.out.print("*"); System.out.println(""); } for(int i=1;i<=n-1;i++) System.out.print(" "); System.out.print("*"); for(int i=1;i<=n;i++) System.out.print("-"); System.out.print("*"); System.out.println(""); int q=n-2; for(int j=2;j<=n;j++) { for(int i=1;i<=q;i++) System.out.print(" "); q--; for(int k=1;k<=2*j-1;k++) System.out.print("*"); System.out.println(""); } } } Less
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import java.util.Scanner; public class webu { public static void main(String[] args) { Scanner sc=new Scanner(System.in); System.out.println("enter the no"); int n=sc.nextInt(); for (int i = n; i >1; i--) { for(int j=1;j1){ for (int l =1 ; l <=2*i-1; l++) { System.out.print("*"); } System.out.println(" "); } } } } Less
written test on basic java you can crack if you are average concept in java.
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But what is the need of exam no result came 2 months have passed i suggest never go and waste your time. Less
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you are right . I have never seen any interview experience that got job offer . at every end of year they have walkin drive . Thats look suspicious . At everytime when you go for interview they ask for reference. It might be true that they hire people who have strong refrence Less
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Yes I got call. May be they call only those people who cracks Aptitude They may have high cut off. Less
If you add an element at a[1] position in arreylist and access a[2] element,what will happen?
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Let arraylist contains {5,6,4,3,1} If you add 2 at 0th position then arraylist become {2,5,6,4,3,1} So according to question you will get old element of a[1] at a[2]'s position Less
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We will get runtime exception:ArrayIndexOutOfBoundException
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Let arraylist contains {5,6,4,3,1} If you add 2 at 0th position then arraylist become {2,5,6,4,3,1} So according to question you will get old element of a[1] at a[2]'s position Less
take input from user...3,5,7 etc and draw a pattern if input is 3 then *** *** * * *** * * * if input is 5 then ***** ***** * * * * * * ***** * * * * *
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code for c language #include #include int main() {int n=7,i,j,l,k,m; for(i=1;i<=n;i++) printf("*"); printf(" "); for(i=1;i<=n;i++) printf("*"); printf("\n"); for(j=1;j<=n-2;j++) { for(k=1;k<=n-1;k++) printf(" "); printf("*"); printf(" "); printf("*"); printf("\n"); } for(i=1;i<=n-1;i++) printf(" "); for(i=1;i<=n;i++){ printf("*");} printf("\n"); for(i=1;i<=n;i++) { for(j=1;j<=n;j++) printf(" "); printf("*"); printf("\n"); } return 0; } Less
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/* if input is 3 then *** *** * * *** * * * if input is 5 then ***** ***** * * * * * * ***** * * * * * */ import java.util.Scanner; public class Pattern3 { public static void main(String[] args) { Scanner sc = new Scanner(System.in); int n=sc.nextInt(); for(int i=1; i<=2; i++){ for(int j=1; j<=n; j++){ System.out.print("*"); }System.out.print(" "); }System.out.println(); for(int i=1; i<=n-2; i++){ for(int j=1; j<=n-1; j++){ System.out.print(" "); }System.out.println("* *"); } for(int i=1; i<=(n+1)/2; i++){ System.out.print(" "); } for(int i=1; i<=n; i++){ System.out.print("*"); }System.out.println(); for(int i=1; i<=n; i++){ for(int j=1; j<=n; j++){ System.out.print(" "); }System.out.println("*"); } sc.close(); } } Less
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check this import java.util.Scanner; public class MyClass { public static void main(String args[]) { Scanner sc =new Scanner(System.in); int n=sc.nextInt(); for(int i=0;i<2;i++){ for(int j=0;j Less
A company uses a format to exchange messages with us. You need to validate the input. The character encoding ASCII. Valid characters are between 0x20 (space) and 0x7E (~). write validate function to generate valid output or the error message.
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public static void printValidMassage(){ String msg="204a6176617e"; String msg1=convertHextoChars(msg); boolean isValid=(msg1.startsWith(" ") && msg1.endsWith("~")) ? true : false; } private static String convertHextoChars(String hex) { StringBuffer sb = new StringBuffer(); for (int i=0; i Less
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public static void printValidMassage(){ String msg="204a6176617e"; String msg1=convertHextoChars(msg); boolean isValid=(msg1.startsWith(" ") && msg1.endsWith("~")) ? true : false; System.out.println(isValid); } private static String convertHextoChars(String hex) { StringBuffer sb = new StringBuffer(); for (int i=0; i Less
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for (int i=0; i
The first question was to print pattern that is n=1 *** n=3 * * *** *** ************ *** *** * * n=5 * * *** *** ***** ***** ******************* ***** ***** *** *** * *
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I don't understand the logic of mid line.... import java.util.Scanner; /* 1 *** 3 * * *** *** ************ *** *** * * 5 * * *** *** ***** ***** ******************* ***** ***** *** *** * * */ public class Pattern1 { public static void main(String[] args) { Scanner sc =new Scanner(System.in); int n=sc.nextInt(); if(n>1){ for(int i=1; i1){ for(int i=(n+1)/2; i>=1; i--){ for(int j=1; j<=(((n+1))/2)+1-i; j++){ System.out.print(" "); } int k=0; while(k != (2*i)-1){ System.out.print("*"); k++; }k=0; System.out.print(" "); while(k!=(2*i-1)){ System.out.print("*"); k++; }k=0; System.out.println(); } } sc.close(); } } Less
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import java.util.Scanner; /* 1 *** 3 * * *** *** ************ *** *** * * 5 * * *** *** ***** ***** ******************* ***** ***** *** *** * * */ public class Pattern1 { public static void main(String[] args) { Scanner sc =new Scanner(System.in); int n=sc.nextInt(); if(n>1){ for(int i=1; i1){ for(int i=(n+1)/2; i>=1; i--){ for(int j=1; j<=(((n+1))/2)+1-i; j++){ System.out.print(" "); } int k=0; while(k != (2*i)-1){ System.out.print("*"); k++; }k=0; System.out.print(" "); while(k!=(2*i-1)){ System.out.print("*"); k++; }k=0; System.out.println(); } } sc.close(); } } Less
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package pattern; import java.util.Scanner; public class webu1 { public static void main(String[] args) { Scanner sc=new Scanner(System.in); System.out.println("enter the no"); int n=sc.nextInt(); for(int i=1;i=1; i--) { for (int j = 0; j < n-i; j++) { System.out.print(" "); } for(int k=0;k<(2*i-1);k++){ System.out.print("*"); } System.out.print(" "); for(int k=0;k<(2*i-1);k++){ System.out.print("*"); } System.out.println(""); } } } Less
How would you measure 4 litres of water if you have 3 litre and 5 litre canisters?
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1) Pour water in 5 litre container 2) Pour 5 litre container into 3 litre until full. You are left with 2 litre in 5 litre container 3) Empty 3 liter container. Pour 2 litre into 3 litre container 4) Fill 5 litre container until full 5) Pour 1 litre into 3 litre container until full. Left with 4 litres in 5 litre container. Less
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Add 2 full measures using the 5l, remove 2 full measures with the 3l, you are left with 4l. Less
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Fill full water in the 5 litre canister, remove 3 liters of it to the 5 litre to the 3 litre canister. Keep remaining in the 5 litre canister(=2 litre) somwhere. Take another 5 litre water and perform the same procedure.= another 2 litre... 2+2 =4 litre.. done. Less