What is the difference between javascript and java ?
JavaScript and Java are two different programming languages with distinct differences in their syntax, design, and use cases.

JavaScript is a scripting language used primarily to create interactive web pages and web applications. It is a high-level, dynamic, and interpreted language that is executed on the client-side (i.e., within the user's web browser). JavaScript is used to add interactivity to websites, create dynamic user interfaces, and perform client-side validation of web forms. It is also increasingly used for server-side programming (using Node.js), as well as for creating desktop and mobile applications.

Java, on the other hand, is a general-purpose programming language that can be used for a wide variety of applications, including desktop, web, and mobile development. It is a compiled language, which means that code must be compiled into machine-readable bytecode before it can be executed. Java is known for its platform independence, which means that compiled Java code can run on any machine that has a Java Virtual Machine (JVM) installed, regardless of the underlying hardware or operating system. Java is used for developing large-scale enterprise applications, Android mobile apps, and other applications that require high performance, reliability, and security.

In summary, while both languages have similar-sounding names, they are used for different purposes and have different strengths and weaknesses. JavaScript is primarily used for creating interactive web pages, while Java is used for developing large-scale enterprise applications and other high-performance software.
I want to make web apps and I'm interested in data science. Which one should I learn?
If your primary goal is to make web applications, JavaScript is the language you should focus on learning. JavaScript is essential for front-end web development, where it is used to create interactive and dynamic user interfaces. It is also widely used in back-end web development through technologies like Node.js, allowing you to create complete, full-stack web applications using JavaScript. Additionally, popular JavaScript frameworks and libraries, such as React, Angular, and Vue.js, are commonly used to build modern web applications.

For data science, Python is typically the preferred programming language. Python has a rich ecosystem of data science libraries and tools, such as NumPy, pandas, Matplotlib, and scikit-learn, that make it easy to perform data analysis, manipulation, visualization, and machine learning tasks. Python's simple and readable syntax also makes it a great language for beginners and experienced developers alike. Jupyter Notebooks, a popular tool for data scientists, provides an interactive environment for writing and executing Python code and visualizing data.

Given your interests, it would be beneficial to learn both JavaScript and Python. Start with JavaScript for web application development, and once you are comfortable with it, you can explore Python for data science. By learning both languages, you'll have the skills needed to create interactive web applications that can also leverage data science techniques for data analysis and visualization.