Dual-Boot system, because the computer hosts more than one operating system, usually 2.
1. 3 times the light voltage, ie., 3*0.5 = 1.5V
2. Total R = 3*25 = 75Ω, V=1.5V, I = V/R = 1.5/75 = 20 mA
3. A 1.5V battery (e.g., an AA battery) with a charge of at least 20mAh. AA batteries should be able to handle this easily.
Go to www.oracle.com , the Downloads tab, find Java, probably SE (Standard Edition) and then select the appropriate SDK (Software Development Kit).
I don't remember if you need to use an absolute (full) path to javac on Windows, but the command is something like:
javac yourProgram
yourProgram needs to be named yourProgram.java
Frank who want to install a software program on a single server with multiple users connected should consider cloud computing. This type of computing delivers convenient, on-demand, pay-as-you-go access for multiple customers to a shared pool of configurable computing resources, which is exactly what Frank needs.