Become an intermediate level Java developer, ready to take on your own projects.

Become a Spring Boot Developer

Learn Java for free with this interactive module, and get a handle on one of the most popular programming languages in the world.

You'll start with a simple hello world program and proceed to cover common concepts such as conditional statements, loop statements, math, and logic in Java, before moving on to more advanced concepts like inheritance, generics, and ArrayLists, along with much more.

Core Java Concepts

# Problem statement

In this problem, you have to implement the *zerosToStart()* function which will sort the elements of an `Integer` ArrayList such that all the _zeros_ appear at left and other elements appear at the right. 

## Function prototype
```java
void zerosToStart(ArrayList<Integer> arrList)
```
## Output
A sorted ArrayList with zeros at the left i.e. starting indices and positive elements at the right. 
## Sample input
```java
arrList = [5,0,20,4,0,0,9]
```

## Sample output
```java
arrList = [0,0,0,5,20,4,9]
```
> **Note:**  All non zero elements must appear in the original order.


In this challenge, you'll implement the solution to gather all the zeros stored in an ArrayList to the starting indices.

Before We Begin

Getting Started with Java!

Variable and User Input

Simple Maths & Logic

Strings and String Processing

Conditional Statements

Loops

Methods

Arrays

Classes and Inheritance

Generics

ArrayLists

Java Exam

Conclusion

Challenge 1: Gathering Zeros to the Start

Problem statement