How to Fix the StringTemplate Invalid Character '<' Error When Reading XML Templates

How can I solve the StringTemplate invalid character '<' error that occurs when reading XML templates?

// Example of causing the issue:
StringTemplate template = new StringTemplate("<template>Invalid Character: <</template>");

The 'invalid character' error in StringTemplate when attempting to read an XML template typically arises due to XML syntax issues, particularly the presence of illegal characters or malformed tags in the XML content. Understanding the reason behind this error can help developers troubleshoot effectively.

// A corrected version:
StringTemplate validTemplate = new StringTemplate("<template>Valid Content</template>"); // Avoid using illegal characters

Causes

• XML syntax errors such as improperly closed tags.
• Using characters that are not permitted in XML templates (e.g., '<' without being part of a tag or escaping).
• Mismatched quoting or special characters that fight against the XML parser.

Solutions

• Ensure all XML tags are properly opened and closed without trailing characters that are not part of a valid XML structure.
• Escape problematic characters within the XML content, for instance, replacing '<' with '&lt;'.
• Validate your XML using online tools or libraries that check for well-formedness before passing it into StringTemplate.

Mistake: Forgetting to escape special characters in XML, such as '<' and '&'.

Solution: Always remember to escape '<' as '&lt;' and '&' as '&amp;' when writing XML content.

Mistake: Using incomplete or invalid tags within the XML template.

Solution: Check your XML structure for completeness and correctness, ensuring all tags are properly nested and closed.