Can you explain the commented part of this Java code? [link on description]

Question

This is a simple code to capitalize every first letter of words in a sentence.

https://code.sololearn.com/c1A5A12A10A1

Answer 1

You can learn about how substring method works by little bit of googling.

as for captializeWord=" " , it is intialization of it with empty string , you will see now why it's important ,

The following code,
"capitalizeWord+=first.toUpperCase()+afterfirst + " "; "

Works like "capitialzeWord=capitializeWord+first.toUpperCase() + afterfirst + " ";

if you didn't initialized it with empty string above you cudn't have done addition to it.