Perhaps you should try some spelling variations:
"using java core snippets" » "using data core snippets"
"dan dat trinh snippets" » "dan dan trinh snippets", "dan lap trinh snippets", "dan dat trong snippets", "dung dat trinh snippets", "dong dat trinh snippets", "dinh dat trinh snippets"
"locating bug code snippets" » "locating bung code snippets", "locating bugs code snippets"

You may be able to get more results by adjusting your search query.

• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"using java core snippets\") OR (\"dan dat trinh snippets\"))) OR (\"locating bug code snippets\"))~".
• Removing quotes may allow a broader search: (((( using java core snippets ) OR ( dan dat trinh snippets ))) OR ( locating bug code snippets ))~.
• Adding a wildcard symbol may retrieve word variants: (((("using java core snippets") OR ("dan dat trinh snippets"))) OR ("locating bug code snippets"))*.