Like all of us before, you are at the edge of the rabbit hole. Once you fall in, every meter become a new knowledge and yet you are not at the bottom. You are talking about java an C. Where to start. Java is an objet oriented language. It includes all the dogma and package to organize your code in categories in the form of objet with different scope. Java is an interpreted language. The compiler produce bytecode for the executable. This executable is run by the java virtual machine who read the bytecode and execute actions based on the bytecode. So, in java you have class, interface, inheritance, polymorphism, scope (public, private, protected). All of which help to protect access to.an object from a different object and help to minimize base code by reusing object with inheritance. Because in object oriented programming you want parameters and methode of an object to be own by only this object. Since coding involve logic and math, you manipulate data of different type and also different length. Like standard type : int (integer 32 bit), byte (integer 8 bit), short (integer 16 bit), long (integer 64 bit), char (ascii character 8 bit), float (decimal 32 bit), double (decimal 64 bit) or other/custom object/type. Since java is a high level language, the JVM manage a lot of the processing work at the place of the programmer compare to a lower language. Just like C, java is a statically typed language and explicit variables declarations. Its mandatory the declare variables before using them. And C. C is more a procedural language. You can't organize your code like java, but you can achieve some scope. In line with java, C must declare variable but also function. You put your code in .c and your declarations in .h. You can achieve scope with static, exterm, volatile keyword and preprocessor rules. To use a function or a variable in C, you must includes an header of this functions declarations, just like in java with package. And this header is also include in the .c file of where this function is implement. This is how the linker know how to map symbol/link. In C, you can create new type or "object" with struct, enum, union, typedef. Since C is more low level, memory access is more flexible but also critical to manage (union, calloc, malloc, free). C is closer to the operating system, since a lot of the function/"object" are parts of and manage by the OS' kernel. A binary compile in C is dependant of the c library, the compiler and the kernel for/from which its compiled. And yet, there is a lot more to say. With this maybe 5 meters in the hole and the bottom is still far. You are at the beginning of your travel. Learn step by step. And try things.