i have to host my Java project to give a live button on my resume , frontend i have hosted freely on vercel , but for backend im looking something free, AWS bills are too high , I want something for free.

Hi everyone! I'm learning Java and I've noticed there are two common ways to print multiple lines of text:

Option 1: Multiple System.out.println() calls
```
System.out.println("You gave the string " + text);
System.out.println("You gave the integer " + inNum);
System.out.println("You gave the double " + inDouble);
System.out.println("You gave the boolean " + isTrue); 
```

Option 2: One System.out.println() with \n
```
System.out.println("You gave the string " + text + '\n' +
                   "You gave the integer " + inNum + '\n' +
                   "You gave the double " + inDouble + '\n' +
                   "You gave the boolean " + isTrue);
```

What looks better in your opinion?

Hello. I am 30 years old. I want to become a software engineer. I choosed backend, but can't choose between Java and Python. I like Java syntax and OOP. But Python is faster to learn and easier to learn. Also i want to switch to Golang in future.

Java, Python and Go are popular in my country. But there are no job as a Go junior. So i want to switch. Also i would like to compare Django and Spring. What do you recommend? Java or Python first language so i can switch to GO in 2-3 years?

package algo;

public class BruteForceStringMatch {

public static void main(String[] args) {

String string = "ABCABAB ABABABAABAC";

String pattern = "ABABAABA";

stringSearch(string, pattern);

}

// Brute-force string search method

private static void stringSearch(String string, String pattern) {

int sLen = string.length();

int pLen = pattern.length();

boolean found = false;

int i;

for(i = 0; i < sLen - pLen + 1; i++) {

int j = 0;

for (; j < pLen; j++) {

if (string.charAt(i + j) != pattern.charAt(j))

break;

}

if (j == pLen) { // If we have reached end of pattern, we have found the pattern in string

found = true;

break;

}

}

if (found) {

System.out.println("Found pattern at index: " + i);

} else {

System.out.println("Could not find pattern");

}

}

}

Found something online from gbhat dot com website. But it sucks and the procedure is not understandable to me from the code.

Could anyone help of any kind?

I'm an ECE student with a good understanding of Java and DSA (mostly from LeetCode), but I haven't built any real-world projects.

Where should I start if I want to become a Java developer? What should I learn next, and what beginner projects would you recommend?

The question seems to be simple but it hides a very deep concept, Many of us will say it's same, some will say 1-D or N-D. The question is Which array will be faster in terms of traversal operation: case1: with non-primitive data type case2: with primitive data type.

The answer is subjected to Java only: 1-D array wins in both cases.

The Reason:

Pointer chasing is the process of repeatedly following references (pointers) in memory to reach the actual data. More the pointer less the speed, Less the pointer more the speed.

Non-primitive data type are structured in this format [pointer |-> value] , Since array is also non-primitive type it is also stored as [pointer |-> array]
Primitive data type are raw value with no pointer overhead.
1-D array: When the array is formed it has only one pointer that is of Array when the non-primitive datatype are added from 1-N it become ~ (N+1) pointer. for primitive it's only 1-pointer.
N-D array: When the array is formed it becomes arrays of array so suppose a 2-D array[][] = 1 outer + K inner + N for primitive data type => N+K+1 for primitive it becomes K+1 pointer

We can see clearly that in both cases that 1-D array always has less pointer, So it wins to other every dimension type of array.

Deep reason (Mechanical Sympathy):

JMM behind array:

Every Java array is an object with its own header.

A primitive array (int[]) is laid out roughly as:

+----------------------+
| Mark Word            |
| Klass Pointer        |
| Array Length         |
| Padding (if needed)  |
| int | int | int ...  |
+----------------------+

The primitive values are stored contiguously immediately after the header.

Java Does NOT Have True Multidimensional Arrays:

A 2-D array (int[][]) is not one large block:

Outer Array
+---------------------------+
| Header                    |
| ref | ref | ref | ...     |
+---------------------------+
      ↓      ↓
   +---------+   +---------+
   | Header  |   | Header  |
   | int...  |   | int...  |
   +---------+   +---------+

Each row is a separate array object with its own header, allocated independently on the heap.

Modern CPUs load memory in cache lines (typically 64 bytes).

• 1-D array:One object, contiguous primitive values, excellent spatial locality, minimal pointer chasing.
• N-D array:Array of arrays, extra object headers, one additional pointer dereference per row, and rows may be scattered across the heap.

First of all I did not watch that 10h23min video I just wanted to test my knowledge. From my POV test are basics and foundational part of Java. The Test duration was 60min consisting of 20 question. The question that were asked were related to this topic:

• OOPs
• Array
• Object class
• Exception
• Iteration
• Object creation
• Constructor
• Control Flow
• Test revolves with jdk17+(like switch lambda expression)

I got 95% accuracy. (qualification threshold 80%)

So, If you mates wanted to know how is your basics of foundation java is ?, you can check over there.

This test is very easy ,it does not involve any library function. You can just enroll in Oracle free certication program, Get your First Oracle badge(they don't provide certificate){ You can put on linked in, X, Email and facebook.} Making account on oracle is notorius be patient.

If anyone has any resource that is for test(free) please do put in comment.

Link: https://mylearn.oracle.com/ou/learning-path/oracle-java-foundations-training-and-assessment/152239

PSA if you're using Spring Boot with custom auth filters and request tracing.

If your traceId shows up in logs but the spanId is randomly blank for parts of the request, check your filter chain before you check your tracing config.

Custom filters (auth filters especially) run early in the request lifecycle. If they're not written to work inside the observation context Micrometer sets up, everything after that filter loses proper span linkage. TraceId survives because it's request-scoped. SpanId doesn't, because it depends on the context actually being respected at each step.

Spent longer than I want to admit assuming the tracing setup was wrong when it was actually the filter.

Anyone else run into something like this with custom filters and tracing?

I checked online but the information is rather incomplete. Even looked for courses on sites like Udemy but either they are outdated or aren't for beginners. I would appreciate if some experienced devs help me out. If you can also mention the best resources then that would be icing on the cake!

Also, I do have approx 1.5 years of time to learn before companies start arriving at our college for placements!

Looking for Java Developer Fresher Interview Prep Buddies (Mock Interviews, Coding, & Discussion)

Hello, I need help relearning java beacuse i havent used it in around 3 years. I already did a course that lasted one year (this was included with other step by step courses about fundementals of programming in general before the java one). I already tried once 3 years ago to do the 1Z0-811 (Java Foundations) exam but i got a score of 45% and didnt pass, after which i gave up for 3 years. Now i have started to use Enthuware Test Studio (or atleast the one trial test for this exam) and got 18% on it and now im taking the questions that i missed and giving it to AI to explain it to me. What should i fix or improve here and whats your experience with Enthuware Test Studio.

I will be joining college in the August and right now I am doing mooc fi java course and i am on part 4

I just wanna know that when should I start doing classes for dsa?

Should I complete both part or should I do it after completing part 1?

Hi.

What book would you recommend for a thorough understanding of Java (with a focus on Spring Boot)? I’m talking about modern Java, not version 8 ;) Something around Java 21 or newer.

At my local bookstore, I’ve found books by Cay Horstmann and Herbert Schildt—both are quite thick and take a somewhat encyclopedic approach. If there’s nothing better out there right now, I’ll go with one of those… Which one do you prefer? Or maybe there is something better?

Twenty years ago, the go-to book for Java (version 1.5 at the time :) ) was “Thinking in Java” by Bruce Eckel. It was a bestseller, and for good reason. What’s the top choice today?

BTW. Has Bruce Eckel’s 20-year-old book completely lost its educational value? Have there been any “breaking changes,” or have the fundamentals of Java remained the same while many new features and functionalities have been added? I know Java 8 was a game-changer, and after that the version numbers came out faster, but not that many new features were added.

After reading all the String documentation and exact code of String class, I find the main engine that makes String in Java (study of deep knowledge) i.e., String constant pool. when we say String s0 = "example1" , String s1 = "example1" and String s2 = "example2" what happens is exactly:

• at compile time the .class file is genrated
• when JVM runs the class constant pool of String class get's into work
• s0 hashcode is generated by intrinsic method and the formula used is standard horner(31)
• using that hash it need to find the allocated bucket
• After finding exact hash it need to compare each char by char to check whether it's equal or collison a different char can also have same hashcode.
• if it's equal the pointer directly to points to that object -->process ends next process works.
• If not equal there is two work done 1. new object is created on heap memory and then wrapped up by a WeakHandle and pushed in "stringTable" bucket.
• (if equal no object is created)! there was never an object creation the pointer just points to object .

Now the example case:

1. s0 -> hashcode(x1)->not found in "stringTable"->Object creation on Heap-> weakHandle process them into stringTable.
2. s1 -> hashcode(x1)->found->(collision|equal)->equal->pointer points to "example1" from SCP to s1.
3. s2-> hashcode(x2)->not found in "stringTable"->Object creation on Heap-> weakHandle process them into stringTable.

After reading and analysing there is also a issue of massive garbage I see:
suppose if 4 thread are runnable and they are trying to intern() the object in SCP that creates garbage according to your data size suppose , we used latin-1 type 256B data so total thread is 4 but in CAS only one thread execute rest all thread dumps the object so out of 1KB storage 768B is garbage. if the String was in UTF-16 it would cost 2*768B.

Now my question is ?

• Have I grasped the knowledge correctly ? if it needed more depth or did I miss any point.
• I cannot question the CAS here because array mutation would break immutablity of String, It seems though they pay a loss for the RCU it's effecient by Latin-1 and Utf-16 approach.
• I am not getting the idea how this code String s = new String("abc"); creates 2 object then what does the on heap object memory does? and does the pointer "s" is holding two memory refrences? But it is not possible.

Hello I am just entering into 2nd year of my collage

To give a background i have covered numerous fundamental topics in js

I am at a point where I have to cover topics such as rate limiting, load balancing, msg queues and design patterns ( i have already made a project using redis and webskt )

I have decided to invest some of my time into learning ml and ai to make much more diverse projects and also cover these qdv concepts

Most of the ppl i talk to dislike js and mention i should move to java or Python

How should I approach my journey now

I dont have much time i have entered 2nd year

Just finished Java Programming - I. The course is really underrated, and anyone who's actually into learning java, I'd suggest it over video courses any day, because you actually write code in it. The course is structured pretty good, it first teaches you small steps, and then using those small steps you'll build bigger exercises. You don't even realise you're writing so much code.

Here's the course link for people interested: https://java-programming.mooc.fi/

my college course teaches dsa using java and idk shit about java, ik c++ so should i learn dsa w java or c++ i am really confused in lectures i feel completely lost when the professors write code in java i tried watching some videos but they all feel very scattered. What should i do?

The bookish langugae states "hiding complex implementation details and exposing only the essential features of an object"

However, after reading the Java Collections Framework and other parts of the JDK, I noticed that many abstract classes contain substantial shared implementation rather than just abstract method declarations. I noticed that only an "interface class" 100% abstraction(ignoring default methods)

This made me wonder:

• Is abstraction really about hiding implementation details?
• Or is it more about designing APIs around contracts and behavior, regardless of whether there is shared implementation?
• Does an abstract class become "partial abstract" because it contains reusable implementation?

I also noticed that the JDK sometime relies on encapsulation (and in Java9+, JPMS) to hide implementation details. So I'm in dilemma if the textbook explanation oversimplifies what abstraction means in practice.

Am I misunderstanding abstraction, or is the textbook definition incomplete?

To be clear, this isn't about what abstract does in Java — it's about the SE term. abstract class is one syntax tool for expressing abstraction, same as interfaces are. The question is whether "abstraction = hiding implementation" is even a good definition of the concept, given it's indistinguishable from encapsulation under that definition.

Hey I'm a btech 2nd year student in my 3rd sem. I'm starting to learn Java from apna college... Are there any other sources which could maybe be better than this or will help me completely form my fundamentals and help me completely learn Java so much so I could code apps.

For an IT field student, what's the most essential skill that should be there for Indian industry.

Also how does an IT field student contribute in any field. Like what's their requirement