Perhaps you should try some spelling variations:
"he truong lop snippets" » "he truong hop snippets", "he truong lon snippets", "he truong long snippets", "he trung lop snippets", "de truong lop snippets", "he trong lop snippets"
"using java java snippets" » "using data java snippets"
"locating bug code snippets" » "locating bung code snippets", "locating bugs code snippets", "locating bug core 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: "((((\"he truong lop snippets\") OR (\"using java java snippets\"))) OR (\"locating bug code snippets\"))~".
• Removing quotes may allow a broader search: (((( he truong lop snippets ) OR ( using java java snippets ))) OR ( locating bug code snippets ))~.
• Adding a wildcard symbol may retrieve word variants: (((("he truong lop snippets") OR ("using java java snippets"))) OR ("locating bug code snippets"))*.